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: THE 19th CENTURY 
Clue: 1853 purchase that brought the contiguous U.S. about up to its present area

SOLUTION: the gadsden purchase

PROBLEM: Category: "R"RRRRR! 
Clue: Frank Gorshin played him on the small screen, Jim Carrey on the big

SOLUTION: the riddler

PROBLEM: Category: THE FIRST PERSON 
Clue: As in a famous JFK quote, it's how one says "I" in German

SOLUTION:
ich