This could be answered, theoretically, in many different ways. All of which might sound a bit dirty. The translation of the sentence is: "What ___ ___ (to) do to Juan on vacation?" I could fill in the blanks with "tú quieres" which would translate the sentence to "What do you want to do to Juan on vacation?" Without choices, that is the best I got.
Answer: Esta
Explanation: there’s not a lot of context but it makes sense because esta means “is” and the sentence would translate to “he is in the class”
