Answer:
YOU
Step-by-step explanation:
This sentence is in the imperative mood. The imperative is a grammatical mood used to give commands, instructions, pieces of advice, warnings or to make requests, that always addresses the second person and whose subject, which is usually implied, is always the second person, that is, “you.”
Therefore, the subject of the sentence, that is, the doer, or the main person being dealt with, is “you.”