At the end of the current year, the accounts receivable account has a debit balance of $1,088,000 and sales for the year total $12,330,000. a. The allowance account before adjustment has a credit balance of $14,700. Bad debt expense is estimated at 1/4 of 1% of sales. b. The allowance account before adjustment has a credit balance of $14,700. An aging of the accounts in the customer ledger indicates estimated doubtful accounts of $47,000. c. The allowance account before adjustment has a debit balance of $8,000. Bad debt expense is estimated at 3/4 of 1% of sales. d. The allowance account before adjustment has a debit balance of $8,000. An aging of the accounts in the customer ledger indicates estimated doubtful accounts of $66,400. Determine the amount of the adjusting entry to provide for doubtful accounts under each of the assumptions (a through d) listed above.