In an assembly design context, which of the following cannot be the work part?

In the context of assembly design, the work part is the part or component you are actively using to modify or create the assembly. The top level of the assembly, component subassemblies, and component piece parts are all integral elements of the assembly structure and represent parts that can be worked on or manipulated within the assembly environment.

A loaded part that does not belong to the assembly is not considered a work part because it does not directly contribute to the design or function of the assembly. It may be present in the design space but lacks relevance to the assembly's integrity or configuration. Work parts need to have a defined role within the assembly, and since the loaded part does not fall under this category, it cannot be actively modified or treated as part of the assembly design process. Thus, it is not considered a valid work part.