Final answer:
The correct tool for assembling shaped pieces without damaging them is a strap wrench. It uses a strap to protect the workpiece, unlike harsher tools like chain wrenches or clamps.
Step-by-step explanation:
When assembling various shaped pieces together without marring the workpiece, the tool to use is a D. strap wrench. A strap wrench provides grip and mechanical advantage similar to other types of wrenches, but it uses a strap made of rubber or other non-marring materials to protect the surface of the workpiece. Unlike a chain clamp or chain wrench that might damage delicate surfaces, the strap wrench is designed to be gentle. Other tools like a power drill or socket wrenches are also useful in similar contexts, as they provide the necessary torque for turning nuts without damaging the material they are applied to.