An indicator that the internal audit activity does not fully conform with the Standards is the presence of any practice that could compromise the objectivity or independence of the auditors. In this case, option C highlights that rotational auditors are performing consulting engagements for areas where they previously had responsibilities, which is a potential conflict of interest and a compromise of objectivity. The other options, such as identifying opportunities for improvement (A), performing a self-assessment with external validation (B), and having external assessments by a competent team every five years (D), do not indicate a lack of conformity with the Standards.