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.

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

Category: ELEMENT NAMES
Clue: Found by Carl Gustav Mosander, terbium is named for Ytterby, a village in this country
sweden

Category: BLACK HISTORY MONTHS
Clue: The 19th of this month is celebrated as the date Texas slaves learned of their freedom in 1865
june