Auditors, like a good set of car tires, need to be rotated every so often. a. Under

Question:

"Auditors, like a good set of car tires, need to be rotated every so often."
a. Under what circumstances, if any, must a lead audit partner be rotated?
b. Under what circumstances, if any, must a concurring audit partner be rotated?
c. Under what circumstances, if any, must an entire audit firm be rotated?