Given the rationale, provide a reasonable question and answer. Step-by-step reasoning process: A skateboarder is someone and if he/she grinds that means he/she is skateboarding.
 The question and answer:
Premise: "Skateboarder grinds a concrete railing."
Based on this premise, can we conclude that the hypothesis "Someone is skateboarding." is true?
Options:
- yes
- it is not possible to tell
- no
The answer is yes