Which of the following transactions is not a money laundering red flag?

a. Premiums are paid through wire transfers from off-shore banks.
b. The customer sets up a recurring draft program to pay premiums quarterly from his checking account.
c. A producer doing business in a neighboring state has a high sales rate but an unusually low policy persistency rate.
d. The customer frequently overpays premiums and asks that the overpayments be returned.