The following control procedures over purchases and cash disbursements transactions are prescribed by the Merlin Company:

1. Approved purchase order for each purchase.

2. Prenumbered receiving report for goods received.

3. Signed receipt from preparer of purchase requisition upon acceptance of goods.

4. Matching of voucher with vendor's invoice.

5. Approved voucher for each check.

6. Cancellation of voucher upon payment.

7. Review of voucher and supporting documentation by check signers.

8. Reorder points for inventory items.

Required:

a. Indicate the function and specific internal accounting control objective served by each procedure.

b. Identify the internal accounting control principle that is involved.

c. Identify an error or irregularity that may be prevented or detected by the control procedure.

d. Indicate a specific test of transactions that may be performed to determine whether the control procedure is operating as prescribed.