A company is trying to set up proper internal controls for their

A company is trying to set up proper internal controls for their accounts payable/inventory purchasing system. Currently the purchase order is generated by the same person who receives the inventory. Together the purchase order and the receiving ticket are sent to accounts payable for payment. What changes would you make to improve the internal control structure?
A. No changes would be made since the person paying the bills is different from the person ordering the inventory.
B. The person in accounts payable should generate the purchase order.
C. The person in accounts payable should generate the receiving ticket once the invoice from the supplier is received.
D. The responsibilities of generating the purchase order and receiving the inventory should be separated among two different people.