Prior to Recording Purchases Transactions, Supplier's Invoices Are Checked and Approved

Prior to recording purchases transactions, supplier's invoices are checked and approved in the accounts department. Controls over this function include all of the following except:

A) marking all supporting documentation as "paid".
B) approving the supplier's invoice for payment by having an authorised person sign the invoice.
C) agreeing the details of the supplier's invoice with the related receiving report and purchase order.
D) determining the mathematical accuracy of the supplier's invoice.