Stop
The stop radical is the same as the stop kanji.
Know your radicals, yo!
し
と, や
None
You have to stop because there is a sheep (し) in front of you. You try to walk around the sheep, but it moves to stop in front of you again. Every time the sheep stops you stop too.
Imagine the fluffy wool of the sheep, stopping you from moving forward. You can't push past it, no matter how hard you try.