An audit team is auditing sales transactions. One step is to vouch a sample of debit entries from the accounts receivable subsidiary ledger back to the supporting sales invoices. The purpose of this audit procedure is to establish that:

A. Sales transactions have been recorded in the proper period.

B. All sales have been properly authorized.

C. Recorded sales actually occurred and pertain to the entity.

D. Discounts and allowances on sales have been properly approved.