Answer:
b. $21,000
Explanation:
The accounting treatment for uncollectable accounts under allowance method is: Bad debts expense Debit and Allowance for doubtful accounts credit.
In the Question carried forward balance of Allowance for Doubtful accounts is $7,000 and the current year's allowance for doubtful accounts in total is $28,000.
So the amount for of bad debts expense for the period would be: