Which two statements are true under the FIDIC Red Book (edition 1999)?

Under the FIDIC Red Book 1999, the Performance Certificate marks the end of the Contractor’s obligations under the contract (Sub-Clause 11.9). The Engineer must issue this certificate once the Defects Notification Period has ended, all Contractor's Documents are submitted, and all works including defect rectification have been completed and tested.

Option C is correct because the Engineer is required to issue the Performance Certificate within 28 days after these conditions are met.

Option D is correct as the certificate is conditional upon fulfilling specific contract requirements (e.g., completion of works, submission of documents).

Option A is incorrect because acceptance of works usually happens earlier (e.g., taking-over certificate); the Performance Certificate represents completion of all contractual obligations, not just acceptance.

Option B is incorrect as the Performance Certificate confirms contractual completion but does not necessarily imply full mutual performance beyond contract terms.