In which of the following scenarios would the internal auditor’s objectivity be best protected?

A former human resources manager conducts an effectiveness review of the appointment and termination process six months after transferring to the internal audit activity.

An accounts payable clerk assists the internal auditors during an effectiveness review of the physical access controls to the server room.

An internal auditor writes the system manual for a newly acquired payroll software application prior to conducting an effectiveness review of the system.

An internal auditor conducts an effectiveness review of an organization's business continuity plan in which his son is a minority stockholder.