A. The auditor must not perform the training, because any task to improve the business process could impact audit independence.

B. The auditor must create a new, separate consulting engagement with the business process owner prior to performing the improvement task.

C. The auditor should get permission to extend the current engagement, and with the process owner's approval, perform the improvement task.

D. The auditor may proceed with the improvement task without obtaining formal approval, because the task is voluntary and not time-intensive.