Which of the Following Types of Documentary Evidence Should the Auditor

Which of the following types of documentary evidence should the auditor consider to be the most reliable?

A) A sales invoice issued by the entity and supported by a delivery receipt from an outside trucker.
B) Confirmation of an account payable balance mailed by and returned directly to the auditor.
C) A check issued by the company and bearing the payee's endorsement that is included with the bank statement mailed directly to the auditor.
D) A working paper prepared by the entity's controller and reviewed by the entity's treasurer.