Providing for Doubtful Accounts

At the end of the current year, the accounts receivable account has a debit balance of $$2,700,000$ and sales for the year total $$32,400,000.$

a$.$ The allowance account before adjustment has a debit balance of $$27,100.$ Bad debt expense is estimated at $\frac{1}{2}$ of $1\%$ of sales.

b$.$ The allowance account before adjustment has a debit balance of $$27,100.$ An aging of the accounts in the customer ledger indicates estimated doubtful accounts of $$128,000.$

c$.$ The allowance account before adjustment has a credit balance of $$17,900.$ Bad debt expense is estimated at $\frac{3}{4}$ of $1\%$ of sales.

d$.$ The allowance account before adjustment has a credit balance of $$17,900.$ An aging of the accounts in the customer ledger indicates estimated doubtful accounts of $$279,000.$

Determine the amount of the adjusting entry to provide for doubtful accounts under each of the assumptions $($a through d$)$ listed above.

a$.$ $ $$

b$.$ $ $$

C$.$ $ $$

d$.$ $ $$