Given the task definition, example input & output, solve the new input case.
Write a correct answer for the question. You should reason about prototypical situations and provide the correct answer. Avoid answers that provide incomplete justification for the question.
Example: at the beach, name something that might protect you from sun.
Output: umbrella
Umbrella can serve as a shield to block the sun

New input case for you: which command should a horse understand before you ride it?
Output:
stop