Please provide a detailed explanation to the following question and explain why the other answer choices are wrong.

[6] A CPA is testing sales transactions. What procedure may (s)he use to test for posting of fictitious accounts receivable? A. Tracing a sample of sales invoices to the accounts receivable subsidiary ledger. B. Sending out negative confirmations. C. Tracing a sample of shipping documents and sales invoices to the sales journal. D. Vouching debits in the accounts receivable ledger to sales invoices and shipping documents