I'll give you a question, please answer with step-by-step reasoning process. He had been stuck in meetings all day, he had to get up and move as he could no longer what?
Options:
- be still
- stay put
- stay still
- sit still
- standing still

Meetings have chairs where people sit. In all day, people sit still for attending the meeting. One gets tired of sitting and needs to move aftre long day.
The answer: sit still.