Option D is a target cost contract with a bill of quantities where the out-turn financial risks are shared between the Client and the Contractor in an agreed proportion. This document contains all the core and secondary option clauses, the schedules of cost components, and contract data relevant to an option D contract. Construction Clients' Board endorsement of NEC3 The Construction Clients' Board (formerly Public Sector Clients' Forum) recommends that public sector organisations use the NEC3 contracts when procuring construction. Standardising use of this comprehensive suite of contracts should help to deliver efficiencies across the public sector and promote behaviours in line with the principles of Achieving Excellence in Construction.