At the end of the current year, the accounts receivable account has a debit balance of $925,000 and sales for the year total $10,490,000. a. The allowance account before adjustment has a debit balance of $12,500. Bad debt expense is estimated at 1/4 of 1% of sales. b. The allowance account before adjustment has a debit balance of $12,500. An aging of the accounts in the customer ledger indicates estimated doubtful accounts of $40,000. c. The allowance account before adjustment has a credit balance of $6,100. Bad debt expense is estimated at 1/2 of 1% of sales. d. The allowance account before adjustment has a credit balance of $6,100. An aging of the accounts in the customer ledger indicates estimated doubtful accounts of $50,600. Determine the amount of the adjusting entry to provide for doubtful accounts under each of the assumptions (a through d) listed above