Answering your own question in an essay

So I’m currently writing an essay and I’ve run into a situation which I’m entirely sure how to resolve. I have asked a question which I am immediately answering (for effect). How do I structure it?

These are the three ways that I’ve considered doing it:

1. "What is the first thing that we see Tim doing, Tim does a backflip."
2. "What is the first thing that we see Tim doing; Tim does a backflip."
3. "What is the first thing that we see Tim doing? Tim does a backflip."

What would be the correct use of grammar here?