The question describes the procurement process for an externally processed activity within an SAP Project System network, which is treated as a service. After the system automatically generates a purchase requisition, the purchasing department selects a vendor and creates a purchase order referencing the requisition. When the vendor performs the service, a service entry sheet is created to document the work. This service entry sheet must then be formally approved (accepted). This acceptance confirms the service was rendered and triggers the posting of actual costs to the project network activity. This sequence is the standard SAP process for procuring external services.

A: This sequence is incorrect because the invoice receipt should occur after the goods receipt or service acceptance, not before.

B: This sequence is illogical. Acceptance of performed services cannot happen before vendor selection and purchase order handling.

D: This option describes the process for procuring materials using a goods receipt, not services. External activities are typically procured as services, which use a service entry sheet for confirmation.

1. SAP S/4HANA Documentation - Help Portal: In the section on "External Processing of Activities," the standard process is outlined. It states, "The purchasing department uses the purchase requisition to select a vendor and create a purchase order... For services that have been performed, you enter service entry sheets. The entry and acceptance of services can be carried out in one step or two separate steps." This confirms the sequence: Vendor Selection -> Purchase Order -> Service Entry Sheet Creation -> Service Entry Sheet Approval.

Source: SAP Help Portal, SAP S/4HANA, Enterprise Portfolio and Project Management, Project System (PS), Structures, Operative Structures, Network, External Processing of Activities.

2. SAP Training Course S4C10 (Business Processes in SAP S/4HANA Project System): Unit 6, "Procurement in Projects," details the process for externally processed activities. It explicitly shows the flow from Purchase Requisition to Purchase Order, followed by Service Entry Sheet creation and then acceptance for services. This directly maps to the sequence in option C.

Source: SAP S4C10 Training Manual, Unit 6: Procurement in Projects, Lesson: Externally Processed Activities. (Specific page numbers vary by manual version but the concept is a core part of this lesson).