Which of the following actions would be most effective to help an internal auditor determine...

Surveying employees to determine whether they are aware of the ethics hotline is the most effective action to help an internal auditor assess how successful the organization has been in communicating the existence of its ethics hotline. Employee surveys can provide direct feedback on their awareness and understanding of the hotline, allowing the auditor to gauge the effectiveness of communication efforts and identify areas where additional outreach or education may be necessary.

The IIA’s Practice Guide on Assessing the Effectiveness of the Ethics Program.

The IIA’s International Professional Practices Framework (IPPF) on Communicating and Reporting.