Final answer:
The responsibilities of internal auditors include being aware of potential fraud risks, determining the control environment's tone, and evaluating control activities, but not guaranteeing that fraud will not occur, which is option A.
Step-by-step explanation:
The internal auditors are integral to an organization, ensuring that the company's controls and processes are effective and working to mitigate risks, including the risk of fraud. However, their responsibilities do not extend to ensuring that fraud will not occur, as this is an unrealistic expectation for any control system.
Instead, their role involves having an awareness of the risk of fraud (being aware of activities in which fraud is likely to occur), assessing the tone at the top set by management (determining whether the control environment sets the appropriate tone at top), and evaluating the effectiveness of control activities within the organization (evaluating the effectiveness of control activities).
Therefore, the option that does not fall under the responsibility of internal auditors is 'A. Ensuring that fraud will not occur.' This is because while internal auditors can work to mitigate the risk of fraud, it is not possible for them to provide an absolute guarantee that fraud will be completely prevented.