The chief audit executive (CAE) manages a large internal audit activity (IAA) reporting functionally to the audit committee and administratively to the chief risk officer. During the CAE's recent unplanned medical leave, several internal audit reports were completed and waiting for CAE approval, however, no formal delegation of authority was in place to anticipate this situation. In order to preserve the independence of the IAA, which of the following would be the most appropriate individual to review and approve these reports during the CAE's absence?