An audit basically consists of having the auditor form an opinion regarding management's financial statement assertions. The auditor therefore develops general and specific program steps to apply to the accounts and transactions. In a particular case, s/he might do this by:A. Tracing sales invoices to shipping documents to tests the completeness of reported sales.B. Tracing shipping documents to sales invoices to test the occurrence of reported sales.C. Tracing sales invoices to shipping documents to test the occurrence of reported sales.D. Tracing sales invoices to shipping documents to test the completeness of recorded accounts receivable.