Answer: estudias
Step-by-step explanation:
In this question, it's simply asking you to conjugate the verb estudiar in the tú form. In any language, verbs are the action of the sentence. So in this example, the verb is estudiar. If you try to translate this sentence, you will say, "In which school do you study?" So now, we automatically know that estudias would be the correct answer. Don't worry, spanish is difficult sometimes, but it's those struggling times that make our spanish stronger.