Which of the following statements regarding sales returns and allowances is correct?

a Recording a sales allowance requires two entries.

b The Sales Returns & Allowances account is an example of a contra-asset account.

c The Sales Returns & Allowances account balance should be added to the Sales account balance when computing net sales.

d Recording sales returns and allowances in a separate account is an important internal control that allows management to evaluate the volume of returns and allowances as a potential indicator of the quality of their products.