12 . Evidence of proper authorization , approval and review of transactions may appear on the face of documents supporting the transactions . Which of the following techniques does not provide evidence of proper authorization , approval or review . A . Purchase orders are signed by the purchasing agent . m Receiving reports are signed by persons inspecting and counting incoming goods . C. Vouchers are signed or initiated by the person comparing vendors' invoices , purchase orders , and receiving reports for prices , quantities , and stock description . D Several checks are signed in advance whenever the treasurer is scheduled to be out of town for an extended period