All of the following would be likely to diminish the validity of evidence obtained through confirmation of accounts receivable except:. a. The return address on the envelope used to send the confirmation request is that of the client.
b. The client's credit manager assists the auditor in selecting the most appropriate customer accounts to confirm
c. The client's mailroom personnel closely monitor and inspect confirmation requests during mailing.
d. The confirmation requests are sent on the client's letterhead.