Allowance for Doubtful Accounts has a credit balance of $557 at the end of the year (before adjustment), and an analysis of accounts in the customer ledger indicates that the estimated amount of uncollectible accounts should be $16,754. Based on the estimate above, which of the following adjusting entries should be made?

1. a. debit Bad Debt Expense, $17,311; credit Allowance for Doubtful Accounts, $17,311
2. b. debit Allowance for Doubtful Accounts, $557; credit Bad Debt Expense, $557
3. c. debit Bad Debt Expense, $16,197; credit Allowance for Doubtful Accounts, $16,197
4. d. debit Bad Debt Expense, $557; credit Allowance for Doubtful Accounts, $557