Which of the following is not a reason why does the audit of accounts receivable and sales

Question:

Which of the following is not a reason why does the audit of and sales presents a significant audit risk?
MULTIPLE CHOICE
a. Significant accounting estimates are used to determine amounts in these areas.
b. Overstatements in this area has been the cause of many financial fraud incidents.
c. Many of the client's customers tend to be disreputable.
d. Overstatements in this area cause net income to be overstated.
Accounts Receivable
Accounts receivables are debts owed to your company, usually from sales on credit. Accounts receivable is business asset, the sum of the money owed to you by customers who haven’t paid.The standard procedure in business-to-business sales is that...