Assume the Following Unadjusted Account Balances at the End of the Accounting

Assume the following unadjusted account balances at the end of the accounting period for Montana Hardware: Accounts Receivable, $80,000; Allowance for Doubtful Accounts, $1,600 (debit balance) ; Sales revenue, $900,000.
If Montana Hardware ages the accounts and determines that $4,000 of the receivables may be uncollectible, the adjusting entry should be:

A) Bad Debts Expense 4,000
$\quad$ $\quad$ $\quad$ $\quad$ Allowance for Doubtful Accounts 4,000
B) Bad Debts Expense 5,600
$\quad$ $\quad$ $\quad$ $\quad$ Allowance for Doubtful Accounts 5,600
C) Bad Debts Expense 2,400
$\quad$ $\quad$ $\quad$ $\quad$ Allowance for Doubtful Accounts 2,400
D) Bad Debts Expense 4,000
$\quad$ $\quad$ $\quad$ $\quad$ Accounts Receivable 4,000