Correct Answer: AThe most appropriate action for the internal auditor is to inform the audit supervisor. This ensures that the issue is promptly elevated to the proper level of authority within the audit function. Informing the supervisor is an essential first step because the supervisor can provide guidance on the appropriate course of action, ensure that the matter is documented correctly, and coordinate any necessary follow-up or additional investigation. This approach aligns with the internal auditor's responsibility to maintain proper channels of communication and reporting within the organization.