An aging of a company's accounts receivable indicates that $9,000 are estimated to be uncollectible. If Allowance for Doubtful Accounts has a $2,400 debit balance, the adjustment to record bad debts for the period will require a 1) debit to Bad Debt Expense for $9,000. 2) debit to Allowance for Doubtful Accounts for $11.400. 3) debit to Bad Debt Expense for $11,400. 4) credit to Allowance for Doubtful Accounts for $9,000.