The correct option is B me to do
Let’s examine the sentence: “What do you want ____ ?” The sentence is in the form of wh-question starting with ‘what.’ We usually form wh-questions with wh- + an auxiliary verb (be, do or have) + subject + main verb. Here the main verb ‘want’ is a transitive verb requiring an object. So, the blank would have a noun or a pronoun first acting as an object to ‘want.’ The words in the blank should begin with a noun or a pronoun. This rules out Options A and C as they are beginning with a preposition. Now, the sentence is a question about the action and so the action is not happening. Option D suggest that the action is happening or action happens by using the verb immediately after ‘me.’ Moreover, 'me do' is a grammatically incorrect phrase. Hence, Option D is ruled out. So, Option B is the correct answer as it brings out the intended meaning of the question.