Final answer:
In account security, independent authorization to make payment is the control that ensures the security of resources in the AP/CD process, acting as a safeguard against unauthorized transactions.
Step-by-step explanation:
The statement inquires about a control measure that ensures the security of resources within the Accounts Payable/Cash Disbursements (AP/CD) process. Each option given relates to internal controls that are part of the process, but the one specifically providing security of resources by monitoring and protecting against unauthorized transactions related to vendor payments is independent authorization to make payment (C). This involves an employee who is separate from the employee requesting the goods or services or receiving them, having the authority to approve the actual disbursement of funds. This control provides a check against fraudulent payments and helps to verify that each payment is legitimate and correctly processed.
Option (A), independent validation of vendor invoice, is about verifying the validity of invoices received, but does not authorize the payment. Option (B), approve vendor selection, refers to the preliminary process of choosing which vendors to do business with, and option (D), requisition confirmation to originating department, deals with confirming that the department that originated the request for goods or services receives what was ordered, but neither of these directly secure the outflow of resources as (C) does.