Answer:
b) an invoice approval initiates the recording of a purchase
Explanation:
A voucher system is used for the authorization of cash payments. Under such a system, a voucher is prepared stating what item is to be purchased, the account which would be charged and the amount of purchases.
Internal controls refer to the system of prevention and detection of frauds and misstatements by the management of an entity to ensure integrity of financial records and transactions.
A voucher system is one of the means of implementing internal controls whereby every purchase can only be processed by sanction of an authority who is authorized to pass the purchase. The voucher issuer and authorizing authority are of course different to ensure independence.