Answer:
d. Another CPA firm
Step-by-step explanation:
A peer review of accounting and auditing practice is required one time every three years for each firms that are enrolled in the American Institute of CPAs (AICPA) Peer Review Program.
The peer review program is supervised by the AICPA but it is carried by an independent evaluator licensed to practice as a CPA, that is, another CPA firm, and approved to carry out the task by the AICPA. The independent evaluator is therefore called the peer reviewer.