All wood parts must be sanded with a belt sander. Some steel parts are sanded with a disk sander.
Some wood parts are sanded at more than one speed.
Ian operate a belt sander.
Each steel part is sanded and etched with the same tool.

Which statement must be true?

Ian operates a sander that has more than one speed.
Only disk sanders are used to etch steel parts.
Some disk sanders can be used for sanding and etching.
Ian sands wood parts
Ian sands and etches items.