According to Implementation Guidance on Independence and Objectivity (Standard 1110), internal auditors may serve in advisory roles as long as they avoid assuming management responsibility. If the CAE assigns a representative to a sensitive steering committee, the choice should be based on relevant expertise and experience to add value without compromising independence. Option D is correct: selecting an auditor with prior experience in mergers or due diligence ensures competence while maintaining objectivity.

Options A and B confuse the role of the auditor with gathering intelligence or strategy promotion. Option C is incorrect, as participation does not require only the CAE.