For the fourth category elimination, Andorra should be accepted for countries ending in A. Also you misspelled America in your "Countries of North America" category. Otherwise nice quiz.
Andorra and Bulgaria are not accepted for European countries that end with A. Also the last clue in the green category is a little misleading. I would say something like "Who was in office at some time after Dwight D. Eisenhower", otherwise it could sound like you mean it's the president that came directly after. Fun quiz tho