Which of the following is NOT a method for fulfilling sales orders?

The correct answer highlights that using a third-party supplier is not a method for fulfilling sales orders within the context of the options provided. Fulfilling sales orders typically involves directly managing the logistics and inventory associated with the orders placed by customers.

Individually fulfilling orders means processing each order one at a time, which allows for personalized service and careful attention to details, ensuring that each customer's needs are met before shipment. Fulfilling orders in bulk involves processing multiple orders at once, which is often more efficient for businesses with high volumes of sales. Customer pickup allows customers to collect their orders directly from the business location, providing a direct and often quicker fulfillment method with no shipping processes involved.

In contrast, fulfilling orders through a third-party supplier can complicate the sales order process. While it is common in dropshipping situations, it does not typically fall under the standard fulfillment methods directly managed by the organization from whose inventory the products would normally be dispatched. The emphasis within the context of sales order fulfillment tends to revolve around internal management of inventory and logistics rather than outsourcing that crucial element of the process.