What type of sourcing rule must be defined for purchase requests for drop suppliers?

A sourcing rule of type buy with a supplier is necessary for purchase requests for drop suppliers because it explicitly defines the relationship between the purchasing organization and the supplier involved in the transaction. This type of sourcing rule allows for the identification of a specific supplier that can fulfill the purchase request, ensuring that the appropriate supplier is selected to deliver goods directly to the customer without the merchandise passing through the seller's facilities.

The requirement for specifying a supplier is crucial in drop ship scenarios, as it eliminates ambiguity and ensures that the purchase order is routed accurately to the designated supplier, maintaining efficiency and clarity in the fulfillment process. This sourcing method enables effective management of supplier relationships and facilitates the accurate handling of inventory movements and deliveries directly from the supplier to the customer.

In contrast, the other options do not meet the specific needs of sourcing for drop suppliers. A default sourcing rule without parameters lacks the definition needed to direct orders to a specific supplier. A customizable sourcing rule may allow modifications, but it does not inherently ensure the direct link to a supplier without specifying one. Lastly, a generic sourcing rule that does not consider the specific supplier could lead to mismanagement of orders, as it might not adhere to the particularities of drop shipping.