Final answer:
The correct option is A) sequence codes. Pre-numbered invoices and pre-numbered purchase orders are examples of sequence codes. Sequence codes are used to assign a unique number to each invoice or purchase order in sequential order.
Step-by-step explanation:
Pre-numbered invoices and pre-numbered purchase orders are examples of sequence codes. Sequence codes are used to assign a unique number to each invoice or purchase order in a sequential order.
The purpose of using pre-numbered invoices and purchase orders is to keep track of the documents and ensure that no document is missed or duplicated in the system.