Which of the following tools is primarily used for marking the outline of a part onto a blank piece?

The tool that is primarily used for marking the outline of a part onto a blank piece is a template. A template serves as a precise guide that allows users to create consistent outlines of a specific shape or profile on materials, aiding in the manufacture or assembly process. By placing the template on the blank piece, the user can trace the outline accurately, ensuring that subsequent cuts or modifications to the material align perfectly with the required specifications.

While a pencil can be used for marking, it does not provide the precision or repeatability that a template does. Similarly, a fixture is used to hold a workpiece in place securely during machining or assembly, and a drill is primarily utilized for creating holes, which is a different function than marking outlines. The focus of the question is on outlining the shape of a part, making the template the most appropriate choice.