Answer:
b. the cash receipts file.
Step-by-step explanation:
Unrecorded liabilities at the end of the accounting period was outstanding so, that the outstanding balance will not be reconciled, if it gets paid then at time of payment the entry is required and the balance will be reconciled. Cash balance cannot determine the outstanding balance. So, accountant will not search the cash receipt file.
All other entries relates to the purchases of the company which could result as a outstanding liability.