Choice "C" is correct. To restrict the risks associated with facsimile responses and treat the confirmations as valid audit evidence, the auditor should consider taking certain precautions, such as verifying the source and contents of a facsimile response in a telephone call to the purported sender.
Choice "b" is incorrect. The auditor could accept the confirmation and not select another customer's balance to confirm provided certain additional procedures are performed, as described above.
Choice "a" is incorrect. The auditor could accept the confirmation and not treat it as an exception provided certain additional procedures are performed, as described above.
Choice "d" is incorrect. The auditor would need to perform additional procedures before accepting the confirmation.