An aging of a company's accounts receivable indicates that $3140 are estimated to be uncollectible. If Allowance for Doubtful Accounts has a $820 debit balance, the adjustment to record bad debts for the period will require a:__________
a. debit to Bad Debt Expense for $3140.
b. credit to Allowance for Doubtful Accounts for $820.
c. debit to Bad Debt Expense for $3960.
d. debit to Bad Debt Expense for $2320.