Which of the following actions is the most appropriate response for an internal auditor to...

When a significant risk is identified during a consulting engagement, the most appropriate response is to report the risk to senior management. Even if the engagement is consulting in nature, it is still crucial for the internal audit activity to ensure that significant risks are communicated to those responsible for managing them.

IIA References:

IIA Standard 2120: Risk Management requires that internal auditors evaluate the effectiveness of risk management processes and communicate significant risks to senior management. This applies regardless of whether the engagement is assurance or consulting.

The Practice Guide on Consulting Services advises that internal auditors must ensure that significant risks identified during consulting engagements are brought to the attention of senior management so that they can take appropriate action.