when auditing a client in the merchandising business, an auditor became concerned that the client was recording fruaduent credit sales. Which of the following procedure would have most likely alerted them to this potential fraud?

A. Observing the credit sales figure on the income statement

B. Recalulation depreciation on fixed assets

C. Analyzing cash receipts as a percentage of sales by month

D. Analyzing gross profit percentage by class of revenue.