When preparing the monthly bank reconciliation, the accountant for Tiffany Toys noted that a check received from a customer last month for $89 was marked NSF and returned along with the bank statement. To correct the cash account balance, the accountant recorded an adjusting entry. This entry required a debit to:
a. Cash.
b. Bad debt expense.
c. Accounts receivable.
d. Sales.
e. None of the above is correct.