Given the rationale, provide a reasonable question and answer. Step-by-step reasoning process: The biker can't have a helmet and no helmet on at the same time.
 The question and answer:
Premise: "One biker wearing a helmet is jumping over an obstacle."
Based on this premise, can we conclude that the hypothesis "One biker wearing no helmet is jumping over an obstacle." is true?
Options:
- yes
- it is not possible to tell
- no
The answer is no