Choice "B" is correct. Policies and procedures should be established for deciding whether to accept or continue a client in order to minimize the likelihood of association with a client whose management lacks integrity.
Choice "a" is incorrect. Suggesting that there should be procedures to decide whether to accept a client does not imply that a firm vouches for the integrity or reliability of a client.
Choice "d" is incorrect. Suggesting that there should be procedures to decide whether to accept a client does not imply that a firm has a duty to anyone but itself with respect to the acceptance, rejection, or retention of clients.
Choice "c" is incorrect. The decision to express an unmodified opinion should be made after the completion of the audit, not upon client acceptance.