Final answer:
The internally generated document that should be compared to the supplier's invoice to verify the price of an item is the 1) purchase order.
Step-by-step explanation:
The internally generated document that should be compared to the supplier's invoice to verify the price of an item is the Purchase order. A purchase order is a document issued by the buyer to the supplier, specifying the details of the items to be purchased, including quantities, prices, and other terms and conditions.
By comparing the purchase order with the supplier's invoice, the buyer can ensure that the prices charged by the supplier are accurate.