Which of the following controls most likely would assure that all billed sales are correctly posted to the accounts receivable ledger?
a. Daily sales summaries are compared to daily postings to the accounts receivable ledger.
b. Each sales invoice is supported by a prenumbered shipping document.
c. The accounts receivable ledger is reconciled daily to the control account in the general ledger.
d. Each shipment on credit is supported by a prenumbered sales invoice.