Under the FIDIC Red Book 2017, Clause 12 [Measurement and Evaluation], specifically Sub-Clause 12.1 [Works to be Measured] , establishes that the Works shall be measured, and payment shall be based on the actual quantities of work executed in accordance with the Contract.

The key principle is that measurement is based on the “net actual quantities” of each item of Permanent Works. This means that only the final in-place quantities are considered, excluding wastage, shrinkage, or temporary excesses unless explicitly stated otherwise in the Contract. Therefore, Option A correctly reflects this fundamental rule.

Option B is incorrect because FIDIC does not generally allow additions for shrinkage or material losses unless expressly provided in the Particular Conditions or Specifications. Measurement is based on completed work, not material input.

Option C is incorrect because if an item is not included in the Bill of Quantities, valuation is determined under Sub-Clause 12.3 [Evaluation], where the Engineer determines appropriate rates—not the Contractor unilaterally.

Option D is incorrect because Option A is clearly aligned with FIDIC provisions.

Thus, Option A correctly represents the measurement methodology under FIDIC Red Book 2017.