Final answer:
Bad Debt Expense is recorded as an estimate in the period of the related credit sales.
Step-by-step explanation:
The correct answer is a. as an estimate in the period of the related credit sales. The allowance method is used to estimate and record Bad Debt Expense, which represents the amount of accounts receivable that is unlikely to be collected. It is recorded in the same accounting period as the related credit sales, based on an estimate of the percentage of credit sales that will become uncollectible.