Comprehensive and Detailed Explanation:
Option A is correct: Certification and payment of interim payments are conditional on Employer's receipt of the Contractor's appointment and the Advance Payment Guarantee (Sub-Clause 14.2.1).
Option D is correct: Payment also requires receipt of the Contractor's statement supported by relevant documentation.
Option B alone is insufficient without supporting documents.
Option C relates to appointment and performance security but is not a stated precondition for payment certification.
References:
FIDIC Silver Book 2017 Edition, Sub-Clause 14.6 - Interim Payment Certificates FIDIC Contract Manager Study Guide, Module on Payment Procedures

According to the FIDIC Yellow Book 2017, the Commencement Date is the date notified by the Engineer as the date on which the Contractor shall start the execution of the Works (Sub-Clause 8.1). In this case, although the Engineer notified 15 July 2022 as the Commencement Date, it was subject to the issuance of the construction permit. Since the construction permit was only obtained on 1 August 2022, work could not legally commence before that date.
FIDIC recognizes that the Contractor cannot be expected to start before all necessary permissions are granted.
Hence, the effective Commencement Date must be the earliest date on which the Contractor can legally commence work, i.e., the date when the permit was issued (1 August 2022). The contract's requirement that the Commencement Date notification occur no later than 14 days after signing is subject to actual readiness conditions (permit availability).
Therefore, for purposes of delay and completion, the Commencement Date is 1 August 2022. This affects the calculation of the Time for Completion and any delay claims accordingly.
References:
FIDIC Yellow Book 2017 Edition, Sub-Clause 8.1 - Commencement of Works
FIDIC Yellow Book 2017 Edition, Sub-Clause 2.1 - Right of Access to Site and Permits FIDIC Contract Manager Study Guide, Module on Contract Formation and Execution

Comprehensive and Detailed Explanation:
Under the FIDIC Silver Book (1999 edition), the Employer may appoint an Employer's Representative to act on their behalf, but this is discretionary and not mandatory (Option B). The Employer's Representative acts within the authority delegated by the Employer but cannot amend the Contract unless expressly authorized.
Option A is partly correct but less complete than B.
Option C is incorrect; the appointment is not compulsory.
Option D is incorrect; the Employer is not contractually obliged to consult the Contractor for appointment approval.
References:
FIDIC Silver Book 1999 Edition, Clause 1.1 and Clause 3 - Employer's Representative FIDIC Contract Manager Study Guide, Module on Contract Administration

Comprehensive and Detailed Explanation:
This statement is true. The Employer administers the contract unless an Employer's Representative or Engineer is appointed to act on its behalf. The Employer (or its Representative) is responsible for reviewing and negotiating claims in good faith with the Contractor to reach agreement, in line with FIDIC procedures.
References:
FIDIC Yellow Book 1999 & 2017 Editions, Clause 3 - Employer's Administration Role FIDIC Contract Manager Study Guide, Module on Contract Administration

Under FIDIC contracts, when defects are identified during Tests on Completion, the Engineer may still issue the Taking-Over Certificate if the defects do not materially affect the intended use (Option A). The Engineer can refuse acceptance until defects are rectified and tests repeated (Option B). The Employer can also request to take over the works (Option C).
However, Option D is not a standard contractual provision; the contract does not stipulate that the Party not liable for rectifying defects is entitled to payment for repeated tests. Typically, costs of repeated tests due to defects are borne by the liable party.
References:
FIDIC Red, Yellow, and Silver Books, Sub-Clause 10.1 and 10.3 - Taking Over and Tests on Completion FIDIC Contract Manager Study Guide, Module on Project Close-Out and Defects