Multiple choice

I had a good chuckle at the following photo.

Here’s a thought bubble if you’d like to think about it before I reveal the answer.

You’d think that, since there are four possible answers, that you should answer 25%. However, there are two choices for 25%, so the chance of picking 25% as your answer is 2/4, or 50%. But there’s only one way to answer 50%, so the answer should be 1/4, or 25%. To quote “The King and I,” et cetera, et cetera, et cetera.

The correct answer, of course, is adding a fifth option: E) 20%.