All of the Statements Concerning Bad and Doubtful Debts Are

All of the statements concerning bad and doubtful debts are correct, except which of the following?

A) The account, doubtful debts expense, is a contra asset account deducted from accounts receivable in the statement of financial position.
B) Bad debts written off is an expense that relates to situations where there is a high degree of certainty that the amount owed will never be paid, e.g., the bankruptcy of the debtor.
C) Doubtful debts relate to amounts unlikely to be received from accounts receivable but where the business is still trying to collect the sum owed.
D) Doubtful debts can be estimated by applying a given percentage to credit sales.