Answered: NEC ECC: Where in option C can I establish who holds responsibility for the design? (I.e D&B or Traditional)

The clause 21.1 of both NEC3 and NEC4 ECC makes it absolutely clear that it has to be clearly stated in the Works Information/Scope what elements of the design Contractor is to do.

This would be further reinforced by whether clause X15 has been specified: if it has not, then the Employer clearly does not intend you to do design.