Final answer:
In welding, some joints use only the base materials being joined; others incorporate a filler material to complete the weld.
Step-by-step explanation:
The question relates to welding techniques and materials. In the context of welding, some welds are created using only the metal of the pieces being joined, which is known as the base material. Other welds involve adding a filler material to the joint to help fuse the pieces together and often to add strength or mass to the weld. Therefore, the correct answer to the question "Some welds are just the local material to make the joint; others use ____ material." is b) Filler.