One of the risks associated with the invoicing function (revenue and receipts cycle) is that goods may be despatched to customers without having been invoiced. Select the most appropriate control to mitigate this risk.

• A. Internal sales orders (ISOs) are filed in numerical order in a temporary file to be matched with the signed delivery note as they come in. Unmatched ISOs are investigated.
• B. The invoicing clerk checks the prices quoted to the customer on the ISO against the official price lists and discount schedules.
• C. On receipt of the goods the customer must sign the delivery notes, retain one copy and return the other to the driver.
• D. The invoicing clerk compares the details of the ISO with the order form.