Fill in the blank with the most appropriate word. A: I’ve planned my future for the next five years. B: That is very clever of you. What _________ when you retire?

The correct answer is A. will you do.

The sentence is about the future, so the verb should be in the future tense. Option B, are you doing, is in the present tense, which is not appropriate for this sentence. Option C, have done, is in the past tense, which is also not appropriate for this sentence. Option D, do you do, is in the present tense, but it is not a complete sentence.

The sentence can be rewritten as “What will you do when you retire?” or “What are your plans for retirement?”