In the context of internal auditing, activities that pose immediate and significant risks to health, safety, the environment, or that conceal inappropriate activities within an organization are of high importance and typically require formal communication to the chief audit executive (CAE). These activities could have severe legal, financial, and reputational consequences for the organization. While acts that favor one party to the detriment of another are concerning and may indicate ethical or procedural issues, they are generally considered less critical compared to the other options, as they do not necessarily imply immediate and severe risks to individuals or the organization as a whole.
Reference:
The Institute of Internal Auditors (IIA) International Standards for the Professional Practice of Internal Auditing (Standards), specifically Standard 2060: Reporting to Senior Management and the Board.
IIA Practice Guide on Communicating Unacceptable Risk.