why the answer is d?

7. (2 pts) AAA Corp had accounts receivable of $750,000 and an allowance for doubtful accounts of the $21,500 just prior to writing off as worthless accounts receivable of $5,000. The net realizable value of accounts receivable as shown by the accounting records before and after the write-off was as follows: a. b. Before After $750,000 $750,000 $721,500 $733,500 $728,500 $723,500 $728,500 $728,500 c. d