At the end of the current year, the accounts receivable account has a debit balance of $858,000 and sales for the year total $9,730,000.

1. The allowance account before adjustment has a credit balance of $11,600. Bad debt expense is estimated at 1/4 of 1% of sales.
2. The allowance account before adjustment has a credit balance of $11,600. An aging of the accounts in the customer ledger indicates estimated doubtful accounts of $37,100.
3. The allowance account before adjustment has a debit balance of $8,000. Bad debt expense is estimated at 3/4 of 1% of sales.
4. 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.