Final answer:
A CIII-CV prescription can be transferred once between pharmacies for refill purposes, subject to specific regulations and recording requirements.
Step-by-step explanation:
According to the regulations concerning controlled substances, a prescription for a Schedule III, IV, or V (CIII-CV) controlled substance may be transferred for refill purposes. These prescriptions can be transferred once. It's worth noting that this transfer can only occur between pharmacies for the purpose of refill dispensing, and it is subject to the transfer being conducted between two pharmacists and the necessary information being recorded. Therefore, the correct answer to the question is (a) Once.