Final answer:
The statement about the OE/S system prompt for a customer number is generally true because the customer number is a vital unique identifier for processing orders and service requests in Order Entry/Sales systems.
Step-by-step explanation:
The statement that the first screen prompt when a customer service representative enters data into the OE/S system is usually for the customer number can be context-dependent but is generally true. OE/S systems, which stands for Order Entry/Sales systems, are designed to manage and process customer orders efficiently. These systems typically require the customer number to access a customer's account information, order history, and any other relevant details that may be necessary to process new orders or service requests. The customer number is often a unique identifier that allows the system to retrieve all pertinent data related to the customer. Hence, it is a logical starting point for many customer service interfaces.