Once you have made that choice, the game may not accept one of the other options. You may well have to work out how to write a quiz in that category.
Future hint for the game - before making your choices, set up a template that you will use, in what looks like the category of choice, and check out the guidelines. That will let you get an idea if it is going to work for you. If not, change the template to be in one of the other options. Eventually, you will have to pick one, and use it. Then you can worry about little details such as a quiz title and subject details.

This idea also works well when you can't work out what the game is requiring of you - I remember some stages where I couldn't tell if it was some specific word needed in the title, or some specific category, or what - just changing that test template, and returning to the game after each change to see if it was accepting the template as potentially fulfilling the criteria, eventually got me there.