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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? a debit Allowance for Doubtful Accounts, $17.600; credit Bad Debt Expense, 517,600 b. debit Allowance for Doubtful Accounts, $21,800, crodit Bad Debt Expense, $21,800 c. debit Bed Debt Expense, $17,600: credit Allowance for Doubtful Accounts, $17,600 d. debit Bad Debt Expense, $21,800, credit Allowance for Doubtful Accounts, $21.800