Why do you think you should not choose what you purchase? There are several versions of the software--read the information and choose according to your situation.
If you are planning on preparing your own taxes and not use Turbotax, and you just want to ask a tax question on this forum, you can pick any product from the menu. PC Desktop Deluxe is a good basic choice. I don't know why Intuit asks that question of people who post questions. Probably for marketing purposes.
@tino14watson Oh.....if you meant you just want to ask a question here and are not really using TurboTax, choosing a product does not matter. Just post a clear and specific question; your "choice" of a TT product will not make a difference, except that often our replies entail help with going to the right place in the software, which will not pertain to you.