Option A is correct: The Engineer is entitled to receive evidence that the Contractor has paid for the necessary insurance policies.
Option C is correct: The Engineer has the role of monitoring the validity of these insurances and ensuring that renewals or extensions are arranged in a timely manner.
Option B is incorrect; the Engineer does not have the authority to take out insurance on behalf of the Contractor.
Option D is incorrect; suspension of construction activities is not automatically the Engineer's role for insurance lapses but may require instructions from the Employer.
References:
FIDIC Red, Yellow, Silver Books 2017 Edition, Sub-Clause 18 - Insurances FIDIC Contract Manager Study Guide, Module on Contract Administration and Insurance

Under FIDIC 2017 editions, the Performance Security protects the Employer against failure by the Contractor to fulfill contractual obligations. The Employer may claim under the Performance Security in the following cases:
Option A: Failure to renew the Tender Security as required during the tendering or contract formation phase can allow Employer to make a claim, since the security guarantees the Contractor's commitments at this stage.
Option E: Failure to extend the validity of the Performance Security when requested or required breaches contractual obligations and enables the Employer to claim under the security.
Option B is incorrect because abandonment without termination notice does not immediately entitle the Employer to claim under Performance Security; formal termination is usually required first.
Option C is incorrect because submitting a claim under Sub-Clause 20.2 (Employer's claims) does not directly correlate with claiming under Performance Security.
Option D is irrelevant; instructions to replace works do not relate to Performance Security claims.
References:
FIDIC Red, Yellow, and Silver Books 2017 Edition, Sub-Clause 4.2 - Performance Security FIDIC Contract Manager Study Guide, Module on Risk Management and Securities

Under FIDIC Silver Book 2017 (EPC/Turnkey), the Contractor bears extensive risk responsibility, particularly for design, site conditions, and data interpretation. However, there are important exceptions- especially concerning errors in the Employer's Requirements.
For the first claim (piling works):
The Employer's Requirements explicitly mandated compliance with a specific national standard (NTS-PW-
01), which contained a proven technical error. Under Sub-Clause 1.9 [Errors in the Employer's Requirements]
, the Contractor is entitled to claim additional cost and/or time if it suffers due to such errors. Since the Contractor relied on a prescribed standard, the risk remains with the Employer. Therefore, this claim is valid.
For the second claim (flood wall):
Although the Site Data contained incorrect hydrological information, under the Silver Book (Sub-Clause 4.10
[Site Data]), the Contractor is deemed to have taken full responsibility for interpreting Site Data. The Contractor assumes the risk of inaccuracies unless expressly stated otherwise. Additionally, "Unforeseeable physical conditions" relief is significantly restricted in the Silver Book compared to Red/Yellow Books.
Therefore, the Contractor is not entitled to additional payment for this item.
Thus, only the piling-related claim is admissible, making Option B correct.

Under the FIDIC Silver Book 1999, Sub-Clause 3.1 [The Employer's Representative] provides that the Employer may appoint an Employer's Representative to act on his behalf. This reflects the optional nature of this role in EPC/Turnkey contracts, where the Employer typically has a more limited involvement compared to Red Book arrangements.
Option B is correct because the contract explicitly allows (but does not mandate) such an appointment. The Employer's Representative can carry out duties and exercise authority as delegated by the Employer.
Option A is incorrect because while neither the Employer's Representative nor any other party can unilaterally amend the Contract, this statement is misleading and not specific to the role defined in the Silver Book.
Option C is incorrect because the appointment is not mandatory; the Employer may choose not to appoint a Representative.
Option D is incorrect because the Employer does not need the Contractor's agreement to appoint an Employer' s Representative. The appointment is at the Employer's discretion, although it must be notified to the Contractor.
This reflects a key feature of the Silver Book: greater Employer control and flexibility, with fewer administrative layers compared to contracts involving an independent Engineer.

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