TASK DEFINITION: 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.
PROBLEM: Category: MILITARY MATTERS 
Clue: Major Esterhazy was probably the real spy for the Germans in this French "affair" that began in 1894

SOLUTION: dreyfus affair

PROBLEM: Category: PRESIDENTS 
Clue: After Garfield's death, he refused to move into the White House until it was redecorated

SOLUTION: arthur

PROBLEM: Category: COMPOSE YOURSELF! 
Clue: At his peak he composed 2 or 3 operas a year like "Lucia di Lammermoor"

SOLUTION:
gaetano donizetti