This is a clear potential conflict of interest (or at least an appearance of one) because a family relationship could influence-or be perceived to influence-the professional's judgment in a procurement decision. NPPE ethics guidance emphasizes early disclosure, transparency, and appropriate conflict management measures.
The best initial action is to disclose the relationship to a supervisor or procurement authority so the organization can decide on mitigation steps (recusal, independent review, altered oversight, or documented safeguards). Option D does exactly that: full disclosure followed by proceeding only under direction (which may include stepping aside). Option A (stepping down) may ultimately be required, but disclosure should come first so the employer can manage the process appropriately and document the decision. Option B is inappropriate because it interferes with a fair tendering process and pressures the bidder; the conflict is the evaluator's, not automatically the bidder's. Option C is insufficient because "being neutral" does not address the appearance of bias and lacks disclosure. Therefore, D is best.