At the planning stage of the audit, the auditor calculates the debtors turnover, the gross profit ratio and the inventory turnover. In comparison with the prior year, results indicate that:

- Debtors turnover has increased;

- Gross profit ratio has decreased; and

- Inventory turnover has not changed significantly.

What is the most likely risk of misstatement identified?

a. Understatement of accounts receivables

b. Overstatement of sales

c. Understatement of sales

d. Understatement of cost of goods sold