Answer:
D) Have no effects on liabilities, assets, or equity
Step-by-step explanation:
When a previously written off account receivable is collected, you must record two separate journal entries. The first one should reverse the write off:
Dr Accounts receivable XYZ
Cr Allowance for doubtful accounts XYZ
Then you record the cash collection:
Dr Cash XYZ
Cr Accounts receivable XYZ
Since both cash and accounts receivable are asset accounts, the collection of the money will not change anything, since one asset account decreases, while the other one increases.
Allowance for doubtful accounts is a contra asset account, so the reversal of the write off will not alter accounts receivable either, because you are adding to it and at the same type subtracting from it.