Answer:
The correct answer is letter "C": when an account is determined to be uncollectible.
Step-by-step explanation:
Bad debt as a result of unpaid credit given to customers can be recorded in the company's books using the allowance method or the direct-write off method. The second approach does not require an allowance account because the account receivable causing the bad debt is directly written-off as an expense whenever the firm decides to tag the account receivable as uncollectible.
The time it takes for a firm to determine that depends on the criteria of its accountants but it is usually extended.