The correct option is D don't you
A question tag is a short question at the end of a statement. It changes a declarative or imperative statement into an
interrogative one. They are mainly used to confirm something or
encourage a reply from the listener.
From the options, "don't you" is the question tag, as it follows the declarative statement "You live in a villa.". Also, it is followed by the question mark, hence option D is correct. "You" is the subject, "live" is the verb and "villa" is the noun that is a part of the adverbial phrase. None of them perform the function of a question tag, hence options A, B and C are incorrect.