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: THE PRESIDENCY 
Clue: In 1998, the highest-ranking person in the line of presidential succession who could not legally be president
madeleine albright

Category: ROYALTY 
Clue: The last king of the Hellenes, he was the second to bear this name
king constantine ii

Category: HISTORIC BOOKS 
Clue: It was written in 1924 in the fortress of Landsberg am Lech

mein kampf by adolf hitler