Consider the question. Can we conclude from "Man working on scaffolding at construction job site." that "A man is working on scaffolding at a construction job site but he isn't wearing his helmet."?
Options:
- yes
- no
- it is not possible to tell
 What is the step-by-step reasoning process to arrive at the answer: it is not possible to tell?
We can't determine that the man isn't wearing his helmet. He may have it on.