Which one of the following statements is correct? Select one: O a. Under the allowance method, you recognize bad debt expenses when account receivable are written off O b. The percentage of receivables method provides the best matching of bad debt expense to the credit sales of a period Oc. The direct write off method of valuing accounts receivable is generally not allowed under GAAP Od. When the percentage of sales methods used, the unadjusted balance for the allowance for doubtful accounts affects the bad debt expense recorded for a period Oe. Accounts receivable are valued on the balance sheet based the amount owned to the business by its customers at the end of the period