Option C is correct: The Contractor is entitled to financing charges (interest) on late payments, calculated as per the percentage specified in the Contract Data or corresponding Sub-Clause.
Option D is correct: The Contractor can suspend works or reduce progress after giving due notice, usually 21 days, if payments are not made on time.
Option A is incorrect; termination is not automatic right after the payment deadline expires.
Option B is incorrect; suspension requires prior notice rather than immediate action.
Option E is incorrect because the Contractor has additional remedies such as suspension, beyond just financing charges.
References:
FIDIC Red, Yellow, Silver Books 1999 & 2017 Editions, Sub-Clause 14.8 - Payment of Retention Money and Financing Charges FIDIC Contract Manager Study Guide, Module on Payment Procedures and Remedies

Option D is NOT correct. The DAAB does not act as a witness or provide support during arbitration. Its role is to avoid and adjudicate disputes early during the project lifecycle impartially and fairly, but it does not serve as witness support in arbitration proceedings.
References:
FIDIC Yellow Book 2017 Edition, Clause 21 - Dispute Avoidance and Adjudication Board FIDIC Contract Manager Study Guide, Module on Dispute Resolution

When the Employer requests a proposal prior to instructing a Variation, the Contractor is typically required to submit:
A description of the varied work (Option A).
Details of resources and methods for carrying out the Variation (Option C).
A Programme showing how the Variation will be executed (Option D).
A description of the proposed design (Option B) is not always required as part of the Variation proposal, especially if the Variation is limited to changes in execution rather than design.
References:
FIDIC Yellow Book 2017 Edition, Sub-Clause 3.4 - Variation Procedure
FIDIC Contract Manager Study Guide, Module on Variations and Change Management

Under FIDIC 1999 (both Yellow Book and Silver Book), Clause 8.1 clearly states that the Contractor "shall commence the design and execution of the Works as soon as is reasonably practicable after the Commencement Date." This clause establishes the formal contractual obligation and timing for starting the Works, but it does not expressly prohibit the Contractor from undertaking preparatory activities-such as preliminary design-before the Commencement Date.
However, any such early design activity is not covered by the contractual protections that apply after the Commencement Date. This means the Contractor proceeds entirely at its own risk. For example, if changes arise due to late Employer requirements, Engineer's instructions, or modifications in the Employer's Requirements, the Contractor cannot automatically claim additional time or cost for rework associated with pre-commencement design.
From a contract management perspective, this reflects a key FIDIC principle: risk allocation follows contractual triggers. Since the Commencement Date activates obligations and entitlements (including EOT and cost claims under Clause 20), activities performed before this date fall outside those mechanisms unless explicitly agreed otherwise.
Therefore, while early design is not forbidden, it is commercially risky, and prudent Contractors typically avoid significant pre-commencement commitments without formal authorization.