Allowance for Doubtful Accounts has a credit balance of $2,100 at the end of the year (before adjustment). and an analysis of customers' accounts indicates uncollectible receivables of $19,700. Which of the following entries records the proper adjustment for bad debt expense? debit Allowance for Doubtful Accounts, $17,600; credit Bad Debt Expense, $17,600 debit Bad Debt Expense, $21,800; credit Allowance for Doubtful Accounts, $21,800 debit Allowance for Doubtful Accounts, $21,800; credit Bad Debt Expense, $21,800 debit Bad Debt Expense, $17,600; credit Allowance for Doubtful Accounts, $17,600 1) 2) 3) 4)