You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

[Q]: Category: OPERAS BY CONTINENT 
Clue: "Aida "
[A]: africa


[Q]: Category: MILITARY MATTERS 
Clue: Major Esterhazy was probably the real spy for the Germans in this French "affair" that began in 1894
[A]: dreyfus affair


[Q]: Category: IT'S A GROUP THING 
Clue: It's a group of bowling teams that compete against each other, or a former association of nations
[A]:
a league