The best way for an IS auditor to determine how well an information security program has been implemented throughout the organization is to perform security risk assessments for the organization’s business units.

D is correct

C. Perform security risk assessments for the organization's business units: This is a valuable practice, but it focuses on identifying potential vulnerabilities, not necessarily the effectiveness of the implemented program in mitigating those risks.

D. Evaluate the integration of security best practices into business workflow.

While evaluating the percentage of employees who have taken security awareness training (Option A) can provide some insight into the level of awareness within the organization, it does not necessarily reflect the effectiveness of the security program's implementation. On the other hand, evaluating the integration of security best practices into business workflow (Option D) provides a more comprehensive assessment of how well the security program has been integrated into everyday operations. This approach examines whether security measures are effectively applied in the organization's processes, procedures, and systems, indicating a more robust implementation of the security program.

perform security risk assessments