4. Quantity Take-Off, Measurement and Bills of Quantities

Introduction and Context

Construction cost estimation depends on the reliability of the quantities being priced. A rate applied to an incorrect quantity produces an incorrect estimate, even when the rate itself is technically sound. Quantity take-off is therefore not a clerical exercise; it is an interpretive and managerial activity that converts design information into measurable work, supports procurement, enables cost control, and establishes a basis for payment and contractual accountability.

In real estate development, measurement connects several decisions. The developer needs quantities to test feasibility and funding requirements. The design team needs them to compare alternatives. The quantity surveyor or estimator needs them to prepare an estimate or bill of quantities (BOQ). Contractors use them to plan labour, materials, plant, subcontracting and cash flow. During construction, measured work supports interim valuations, variations, final accounts and claims.

The process is complicated by the fact that drawings and specifications rarely describe a project in one perfectly coordinated source. Information may be distributed across architectural drawings, structural drawings, services layouts, schedules, specifications, geotechnical reports and digital models. Measurement consequently involves interpretation, classification, assumptions and checking. This chapter examines those activities and shows how a defensible BOQ can be prepared while managing ambiguity and measurement risk.

Learning Objectives

By the end of this chapter, the learner should be able to:

1. Explain the purpose, principles and terminology of construction measurement and quantity take-off.

2. Interpret drawings, specifications and digital models to extract measurable work.

3. Select suitable units, descriptions and measurement methods for different work items.

4. Prepare dimension sheets, quantity abstracts, schedules and bills of quantities.

5. Distinguish between measured work, provisional items, prime cost items, contingencies and exclusions.

6. Identify omissions, ambiguities, double counting and other sources of measurement risk.

7. Apply quality assurance, digital tools and professional controls to improve reliability.

8. Use measured information for procurement, cost management, valuation and decision-making.

Measurement as the Language of Construction Cost

Measurement is the systematic determination of the extent of construction work. Quantity take-off is the extraction of those quantities from available project information. The result may be a preliminary quantity estimate, a detailed measurement, a schedule of quantities or a formal BOQ. These outputs differ in purpose and level of certainty, but all require a clear relationship between the described work and the quantity reported.

A measured item normally contains three connected elements: a description of the work, a unit of measurement and a quantity. For example, “in-situ reinforced concrete in suspended slabs, including placing and compacting” may be measured in cubic metres. The description defines what is included; the unit defines how extent is expressed; and the quantity records the calculated amount. A rate can be applied only when the description and unit are sufficiently precise.

Measurement must be consistent. Similar work should be classified in similar ways throughout the document, and work should not be measured twice merely because it appears on more than one drawing. A wall shown architecturally may also appear in a structural or fire-safety drawing; the estimator must identify the authoritative information and avoid duplication.

Important terminology

A dimension sheet records the dimensions and calculations used to derive quantities. A taking-off list is the working list of items extracted from the documents. An abstract groups similar measured items and totals them. A schedule of quantities presents work items and quantities, often for pricing or procurement. A bill of quantities is a structured contractual or tender document containing descriptions, units and quantities, and frequently spaces for rates and amounts.

A work breakdown structure (WBS) divides the project into hierarchical packages such as substructure, frame, envelope, finishes and services. A work package is a manageable portion of that structure assigned for planning, procurement or execution. Net quantity is the calculated physical quantity before specified allowances; gross quantity may include areas or volumes measured without deductions according to the applicable rules. A waste allowance covers expected material loss and should not be confused with additional construction work.

A provisional sum is an allowance for work whose extent or nature cannot be adequately defined at tender stage. A prime cost (PC) sum is an allowance for the supply of specified goods, usually excluding associated installation unless stated otherwise. Preliminaries cover general obligations and site-related costs, such as mobilisation, temporary facilities, supervision and health and safety arrangements. Daywork is a valuation method for work paid according to recorded labour, plant and material inputs when it cannot conveniently be valued using ordinary rates.

Sources of Measurement Information

The first professional task is not calculation but information control. The estimator should establish a document register showing drawing number, title, revision, date and status. A tender or estimate should never silently combine superseded and current drawings. The register should also identify specifications, schedules, addenda, clarification responses and model versions.

Architectural drawings generally provide room layouts, dimensions, finishes, doors, windows and elements of the building envelope. Structural drawings provide foundations, reinforcement information, columns, beams, slabs and structural openings. Mechanical, electrical and public-health drawings describe services, equipment, routes and connection points. Specifications define quality, materials, workmanship, testing and inclusions that may not be visible in drawings. Site information affects excavation, disposal, temporary works and external works.

The estimator must develop a hierarchy of reliance. Where documents conflict, the contract conditions or measurement rules may establish precedence. In other situations, the conflict should be recorded as a query rather than resolved by personal assumption. An unresolved ambiguity is a risk item, not an invitation to conceal uncertainty inside a rate.

Measurement Rules, Units and Descriptions

Measurement systems vary by jurisdiction and contract. Examples include national standard methods of measurement, institutional methods, trade-specific rules and client-specific templates. The selected rules determine such matters as deductions for openings, treatment of junctions, measurement of formwork, reinforcement, excavation and disposal, and whether certain ancillary work is included in a composite item. A professional estimate should state the measurement basis and edition used.

Common units include:

• cubic metre (m³) for concrete, excavation and bulk fill;
• square metre (m²) for formwork, plastering, flooring, roofing and painting;
• linear metre (m) for pipes, kerbs, skirtings and certain trims;
• kilogram or tonne for reinforcement and structural steel;
• number (nr) for doors, sanitary fittings, luminaires and equipment;
• item or lump sum for defined obligations that are not usefully measured by physical extent.

The unit should reflect the cost-driving characteristic of the work. A pipe may be measured by length, but fittings, testing and connections may require separate items. A door is measured by number, but its description should identify type, size, fire rating, frame and hardware where those features affect cost.

Descriptions should be sufficiently complete to distinguish one item from another. A weak description such as “brickwork” leaves unanswered questions about thickness, material, bond, finish, location, strength and associated work. A stronger description identifies the material, dimensions or performance, location and significant inclusions. Excessive description is also undesirable if it obscures the pricing structure. The goal is unambiguous, comparable and measurable work.

A Reliable Quantity Take-Off Workflow

Establish the measurement strategy

Before taking off quantities, define the purpose: feasibility estimate, cost plan, tender BOQ, procurement schedule, valuation or final account. Establish the level of detail, measurement rules, classification system, currency, tax treatment and required output. A feasibility estimate may use floor-area rates and major elemental quantities; a tender BOQ requires substantially more detailed descriptions and coordination.

Read the project before measuring it

A complete review should begin with the site, building form, structural system, floor levels, circulation, services strategy and external works. Measuring a single drawing in isolation encourages omissions. A first review should identify unusual features such as transfer structures, retaining walls, basements, façade systems, specialist equipment, complex landscaping or phased construction.

Build the item list

The estimator then creates a work breakdown and a taking-off list. A conventional sequence might include preliminaries, demolition, site preparation, earthworks, substructure, frame, upper floors, roof, external walls, internal walls, finishes, fittings, services, external works and testing or commissioning. The sequence should support both measurement and later cost reporting.

Extract dimensions and calculate

Dimensions are taken from drawings, schedules or models and recorded with their source reference. Calculations should be visible rather than hidden in a final total. For example, the volume of a rectangular foundation may be calculated as length × width × depth, while a wall area may be calculated from length × height less permitted deductions. Repeated elements should be identified systematically, but repetition must be checked against plans, elevations and sections.

A dimension sheet might contain columns for item reference, location, dimensions, number, multiplication factor, calculated quantity, unit, drawing reference and remarks. Arithmetic can be performed using spreadsheets or software, but the source and logic should remain auditable.

Abstract and classify

Similar items are collected into an abstract. For example, concrete in footings, columns, beams and slabs may be separated because their rates and construction conditions differ, even though all are measured in cubic metres. The abstract checks that all dimension-sheet items have been transferred and provides a bridge between raw take-off and the priced BOQ.

Draft the BOQ or schedule

The BOQ presents items in a logical order, with item numbers, descriptions, units and quantities. Where pricing is required, it may include rate and amount columns. It should also identify preliminaries, provisional sums, PC sums, attendance, testing, temporary works and other items that might otherwise be hidden in rates.

Check and reconcile

Checking is undertaken at several levels. Arithmetic checking tests calculations and extensions. Cross-checking compares quantities against another method or an independent measurer. Drawing reconciliation confirms that plans, sections, elevations and schedules agree. Benchmarking compares quantities with floor area, storey count, structural grids or similar projects, but benchmarks are warning indicators rather than substitutes for measurement.

Measurement of Selected Work Categories

Earthworks and substructure

Earthworks require careful distinction between excavation, disposal, filling, imported material, compaction and temporary support. Quantities may depend on formation levels, soil categories, working space, batter slopes and groundwater conditions. Excavation measured from a drawing may not capture the risk of unstable ground or restricted access; such matters belong in assumptions, risk allowances or separate temporary-work items.

Concrete should normally be separated by structural function and specification where these affect cost. Reinforcement may be measured by mass, bar schedule or allowance, but the basis must be stated. Formwork is generally measured by contact area, subject to the relevant rules. Waterproofing, blinding, membranes, joints and protection should not disappear merely because they are associated with concrete.

Walls, finishes and openings

Wall measurement requires attention to thickness, material, height, location and finish. Openings may be deducted according to the measurement rules, while reveals, sills, lintels, frames and trims may need separate measurement. Finishes should be classified by substrate, material, thickness, pattern, performance and location. A floor finish schedule is often an efficient control because it links room areas with specified finishes.

Doors, windows and façade work

Openings are frequently under-described. A door schedule can provide number, dimensions, material, fire or acoustic rating, frame and hardware. Windows and curtain-wall systems may require separate measurement for frames, glazing, spandrels, seals, flashings and access provisions. Façade measurement should reconcile elevations with plans and sections so that corners, parapets, openings and interfaces are not omitted.

Services and external works

Services quantities are best coordinated with equipment schedules, schematic diagrams and layouts. A pipe length from a plan may exclude risers, drops, offsets, insulation, valves, supports, testing and commissioning. Electrical quantities should distinguish containment, cabling, wiring devices, luminaires, distribution equipment and testing. External works require coordination of levels, drainage, paving, kerbs, planting, boundary works and utility connections.

From Take-Off to a Defensible Bill of Quantities

A BOQ has both commercial and technical functions. It allows tenderers to price a common scope, enables comparison of tenders, supports interim valuation and provides a structure for variations. It does not remove the need for drawings and specifications; rather, it organizes and quantifies them.

A useful BOQ contains:

1. project and document information;

2. preliminaries and general obligations;

3. measured work arranged by trade, element or construction sequence;

4. provisional and prime cost items, clearly identified;

5. attendance, testing, commissioning and close-out requirements;

6. a summary of sections and totals;

7. notes on measurement rules, assumptions, exclusions and taxes.

The distinction between measured work and allowances is particularly important. If a quantity is known but its final design is not, it may be measured with an appropriate description and qualified assumption. If the work itself cannot reasonably be defined, a provisional sum may be appropriate. Using provisional sums merely to avoid measurement transfers uncertainty into contract administration and weakens cost control.

A schedule of quantities for procurement should also state whether quantities are fixed, estimated, remeasurable or for comparison only. The legal effect depends on the contract. The person preparing the document must not assume that a BOQ has the same status under every procurement route.

Managing Assumptions, Omissions and Measurement Risk

Measurement risk arises from incomplete information, inconsistent documents, incorrect interpretation, arithmetic error, duplicated work, inappropriate units, uncertain ground conditions, design development and changes in scope. Risk management begins with making uncertainty visible.

An assumptions register should record the issue, assumption, source, responsible person, cost or quantity impact, probability, consequence, required action and status. Examples include assumed ceiling heights, extent of rock excavation, provisional façade details, allowance for service diversions and interpretation of opening deductions. Assumptions should be dated and linked to drawing or correspondence references.

An omissions schedule is equally valuable. It lists work not included in the current estimate, such as loose furniture, statutory charges, abnormal foundations, utility upgrades, tenant fit-out or specialist systems. An omission is not necessarily an error if it is deliberate and disclosed; it becomes a serious problem when stakeholders believe it is included.

Common errors include:

• measuring from superseded drawings;
• omitting vertical work, risers, roof edges or external works;
• double counting work shown in architectural and structural information;
• applying a generic rate to work with materially different conditions;
• mixing net and gross areas without disclosure;
• treating a provisional sum as though it were a firm quantity;
• failing to include testing, protection, access or commissioning;
• hiding design uncertainty inside an unexplained contingency;
• relying on a model without checking its classification and completeness.

A mature review distinguishes between quantity risk, rate risk, scope risk and price risk. Quantity risk concerns the extent of work; rate risk concerns productivity, material or labour pricing; scope risk concerns what is included; and price risk concerns market movement, escalation or currency. Different risks require different responses.

Digital Measurement, BIM and Data Governance

Digital tools can improve speed and traceability, but they do not eliminate professional judgement. Two-dimensional take-off software can calculate areas and lengths directly from calibrated drawings. Spreadsheet models support formulas, version control and reconciliation. Building information modelling (BIM) can provide quantities through schedules, object properties and model-based measurement.

Model-based take-off is reliable only when the model is sufficiently developed, objects are correctly classified, quantities are not duplicated across linked models, and model properties correspond with specifications. A model may represent design intent without representing temporary works, waste, installation access or procurement packaging. Therefore, model quantities should be tested against drawings and site requirements.

A controlled digital workflow should include model and drawing version identification, permissions, change logs, naming conventions, validation rules and review sign-off. Automated quantity extraction should flag unusual zero quantities, missing classification codes, inconsistent units and significant changes between revisions. Artificial intelligence may assist with drawing recognition, object classification and anomaly detection, but outputs require human verification because visual similarity does not establish contractual scope.

Digital governance also includes cybersecurity and data integrity. Commercial quantities, rates and tender information may be sensitive. Access should be role-based, files should be backed up, and changes should be attributable. A technically sophisticated system with weak information governance can create greater rather than lower risk.

An Illustrative Case: The Riverside Apartments BOQ

Background

Riverside Apartments is an illustrative 12-storey residential development with two basement levels, reinforced-concrete frame, brick-and-glass façade, mechanical ventilation and landscaped external works. The developer requires a tender BOQ for a design-and-build procurement package. Architectural, structural and services information has reached different levels of development.

Situation and problem

An initial estimate prepared from the architectural model was 8 per cent below the approved cost plan. The apparent saving seemed attractive, but the project manager suspected that the model excluded construction interfaces. The basement excavation was modelled, but disposal, groundwater control and temporary retaining measures were not defined. The façade model represented glazing but did not clearly identify support brackets, flashings or access requirements. Services schedules also contained equipment without corresponding installation allowances.

Analysis

The measurement team established a document register and compared model quantities with structural drawings, elevations, equipment schedules and specifications. A classification review found that some linked model elements were counted twice, while balcony slabs and roof plant supports were absent. The team separated firm measured work from design-dependent items and created an assumptions and omissions register.

A reconciliation showed that the estimate’s principal weakness was not a single arithmetic error. It was scope incompleteness: basement temporary works, external connections, façade interfaces, commissioning and several specialist installations had not been represented in the model-derived quantities. The team also identified inconsistent treatment of openings in wall areas.

Approach and solution

The team adopted a hybrid process. Quantities for concrete, formwork, reinforcement and architectural finishes were taken from coordinated drawings and checked against model schedules. Services were measured using layouts and equipment schedules, with separate items for supports, insulation, testing and commissioning. Basement risks were described as provisional or risk allowances only where the information genuinely could not be developed. An explicit exclusion was made for tenant loose furniture.

The BOQ included a responsibility matrix showing whether each item was by the main contractor, a specialist subcontractor or the client. Each significant assumption received a reference in the BOQ notes. An independent quantity surveyor reviewed the abstract and performed floor-area and structural-grid benchmark checks.

Outcome

The revised tender document produced a higher but more credible estimate. Tenderers priced a common scope, and clarification questions were concentrated on a small number of identified design-development items rather than hidden omissions. During tender analysis, the developer could distinguish genuine price competition from differences in scope. The BOQ also provided a usable structure for later valuation and variation control.

Learning points

The case demonstrates that digital extraction is a source of evidence, not an automatic guarantee of completeness. A reliable BOQ depends on document coordination, explicit assumptions, correct classification and independent checking. It also shows why the cheapest initial estimate may not be the lowest-cost decision: apparent savings created by omission often reappear as variations, claims or programme disruption.

Professional and Ethical Considerations

Measurement professionals have a duty to present information honestly and with appropriate qualification. Deliberately understating quantities to achieve an attractive feasibility result, concealing exclusions, or manipulating descriptions to favour a bidder undermines informed decision-making. Professional independence is especially important where the estimator is pressured by a client, contractor or design team.

Confidential rates and tender information should be protected. Conflicts of interest should be declared, and document revisions should be traceable. Regulatory requirements may affect measurement of accessibility provisions, fire safety systems, energy performance, environmental works and health and safety obligations. The estimator should not treat regulatory compliance as an optional addition to the BOQ.

Measurement is also connected to sustainability. Quantities can support embodied-carbon analysis, waste planning, material passports and circular procurement. However, environmental data must be based on defined boundaries and verified product information. A quantity take-off that ignores demolition waste, replacement cycles or material wastage can give a misleading impression of project performance.

Current Developments and Best Practice

Contemporary practice is moving from isolated quantity production toward integrated cost and information management. Five-dimensional BIM links model objects with quantities, rates and cost codes. Cloud collaboration enables concurrent review, while automated comparison tools identify changes between drawing revisions. Parametric design allows quantities and costs to be tested as form, area or specification changes.

These developments increase the importance of data standards and classification. Organisations need consistent codes, templates, naming conventions and measurement rules if information is to move reliably between design, estimating, procurement and cost reporting systems. The more automated the workflow becomes, the more important it is to define responsibility for validating outputs.

A best-practice measurement process therefore combines:

• a clearly stated measurement basis;
• controlled and current source documents;
• a logical WBS and coding system;
• visible calculations and source references;
• separation of firm quantities, allowances and exclusions;
• independent arithmetic and scope checks;
• reconciliation between drawings, specifications and models;
• a maintained assumptions, queries and omissions register;
• documented approvals and revision history;
• review of the BOQ for procurement and contract suitability.

Chapter Summary

Quantity take-off converts design and project information into measurable work. Measurement is not simply arithmetic: it requires interpretation, classification, document control and professional judgement. A reliable process begins by establishing the purpose, measurement rules and current information sources; proceeds through systematic extraction, calculation and abstraction; and ends with a checked BOQ or schedule.

Descriptions, units and quantities must work together to define scope clearly. Preliminaries, provisional sums, prime cost items, testing, commissioning and exclusions should be identified rather than hidden in rates. Measurement risk is managed through reconciliation, independent checking, assumptions registers, omissions schedules and clear allocation of responsibility. Digital take-off and BIM improve speed and traceability, but model quality and human validation remain essential. When prepared carefully, a BOQ supports tender comparison, procurement, valuation, cost control and fair contract administration.

Key Terms

Quantity take-off: Extraction and calculation of measurable construction work from project information.

Measurement: Systematic determination of the extent of construction work using defined rules.

Dimension sheet: Record of dimensions, calculations, sources and resulting quantities.

Abstract: Consolidated grouping and totaling of similar measured items.

Bill of quantities: Structured document describing and quantifying work for pricing, procurement or contract administration.

Work breakdown structure: Hierarchical division of a project into elements, trades or work packages.

Unit of measurement: Standard expression used to quantify an item, such as m², m³, kg or number.

Preliminaries: General site and project obligations not normally represented as permanent measured work.

Provisional sum: Allowance for work whose extent or nature cannot be adequately defined at the relevant stage.

Prime cost sum: Allowance for specified goods, generally excluding associated installation unless stated.

Daywork: Valuation method based on recorded labour, plant and material inputs.

Net quantity: Calculated quantity before specified allowances or additions.

Waste allowance: Quantity added to account for expected material loss during handling or installation.

Assumptions register: Controlled record of interpretations used where project information is uncertain.

Omissions schedule: List of work deliberately excluded or not yet included in an estimate or BOQ.

Measurement risk: Risk of error or uncertainty in scope, quantity, classification or interpretation.

Reconciliation: Comparison of quantities or information from different sources to identify discrepancies.

BIM: Digital representation of building information that can support coordinated design and quantity extraction.

Five-dimensional BIM: BIM extended to include quantities and cost information.

Review Questions

Short Answer Questions

1. What is the relationship between quantity take-off and a bill of quantities?

2. Why should a measurement basis be stated in a BOQ?

3. Distinguish between a provisional sum and a prime cost sum.

4. State four sources of information used in construction measurement.

5. What is the purpose of an assumptions register?

Long Answer Questions

1. Explain the complete workflow for preparing a reliable BOQ, from document review to final checking.

2. Discuss how descriptions, units and measurement rules influence the pricing and contractual usefulness of measured work.

3. Explain the principal measurement risks in earthworks, substructure, façade and building services.

4. Evaluate the benefits and limitations of BIM-based quantity take-off.

5. Discuss the professional and ethical responsibilities involved in preparing quantities for a major development.

Analytical / Application Questions

1. A tender BOQ is 10 per cent below the cost plan because the digital model contains concrete and glazing but no temporary works, testing, commissioning or façade access provisions. Diagnose the problem and propose a review strategy.

2. Two estimators produce different wall quantities: one deducts all openings and the other measures gross wall area. Identify the information needed to resolve the difference and explain how the BOQ should record the decision.

3. Prepare a measurement-risk response for a basement project where soil conditions, groundwater and disposal routes are uncertain. Distinguish firm quantities, assumptions, provisional items and exclusions.

22. Multiple Choice Questions with Answers

Question 1

Which sequence best represents a reliable quantity take-off workflow?

A. Price rates, select drawings, prepare a summary, then measure

B. Establish purpose and information, extract dimensions, abstract, draft, and check

C. Prepare a contingency, model the building, invite tenders, then classify items

D. Measure only the architectural drawings and adjust quantities after construction

Correct Answer: B. Establish purpose and information, extract dimensions, abstract, draft, and check

Question 2

What is the principal purpose of an abstract in measurement?

A. To replace the project specifications

B. To record only provisional sums

C. To group and total similar measured items before BOQ preparation

D. To calculate contractor profit

Correct Answer: C. To group and total similar measured items before BOQ preparation

Question 3

Which item is most appropriately treated as a provisional sum when tender information is incomplete?

A. A fully dimensioned concrete slab with a stated specification

B. A defined number of standard internal doors

C. A completely designed floor finish measured by area

D. Groundwater control whose extent cannot yet be established

Correct Answer: D. Groundwater control whose extent cannot yet be established

Question 4

Why can a BIM-generated quantity not be accepted automatically without review?

A. BIM models never contain dimensions

B. Models may omit scope, contain duplicated objects or use incorrect classifications

C. BIM cannot represent building services

D. Digital quantities cannot be compared with drawings

Correct Answer: B. Models may omit scope, contain duplicated objects or use incorrect classifications

Question 5

Which practice most directly reduces the risk of measuring superseded information?

A. Using the oldest drawing because it has fewer revisions

B. Relying on contractor memory

C. Maintaining a controlled document register with revision and status information

D. Including all drawing versions in the final BOQ

Correct Answer: C. Maintaining a controlled document register with revision and status information

Question 6

A door description states only “door, number: 20.” What is the main deficiency?

A. The unit is necessarily incorrect

B. The description does not identify characteristics that may affect scope and price

C. Doors must always be measured in square metres

D. A door cannot appear in a BOQ

Correct Answer: B. The description does not identify characteristics that may affect scope and price

Question 7

Which example best illustrates double counting?

A. Measuring excavation and imported fill as separate operations

B. Measuring a wall once from the architectural plan and again from the structural drawing without reconciliation

C. Separating concrete columns from concrete slabs

D. Listing testing separately from equipment supply

Correct Answer: B. Measuring a wall once from the architectural plan and again from the structural drawing without reconciliation

Question 8

What is the most appropriate response when a design ambiguity affects quantity but cannot yet be resolved?

A. Conceal it within an unexplained rate

B. Delete the affected work from the BOQ

C. Record it as an assumption or query and identify its cost implication

D. Assume the least expensive interpretation without disclosure

Correct Answer: C. Record it as an assumption or query and identify its cost implication

Question 9

Which distinction is correct?

A. Quantity risk concerns extent; rate risk concerns the cost applied to the extent

B. Quantity risk and rate risk are identical

C. Rate risk concerns only drawing revisions

D. Quantity risk applies only to services

Correct Answer: A. Quantity risk concerns extent; rate risk concerns the cost applied to the extent

Question 10

In the Riverside Apartments case, the initial model-based estimate was unreliable mainly because it:

A. Used too many independent checks

B. Included all temporary works and commissioning

C. Combined current drawings into a controlled register

D. Failed to represent several interfaces, scope items and design-dependent works

Correct Answer: D. Failed to represent several interfaces, scope items and design-dependent works