Which of the following forms of information should the auditor consider to be the most$$ reliable?

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Part $1$

$1.$

A sales invoice issued by the client and supported by a delivery receipt from an outside trucker

$2.$

An electronic confirmation of an account payable balance mailed by and returned directly to the auditor

$3.$

A$$ cheque, issued by the company and bearing the$$ payee's endorsement, that is included with the bank statements mailed directly to the auditor

$4.$

An estimate of warranty provision prepared by the$$ client's controller and reviewed by the$$ client's treasurer