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: TELEVISION HISTORY 
Clue: Set in the 1870s, it ran from 1955 to 1975

SOLUTION: gunsmoke

PROBLEM: Category: AMERICAN CITIES 
Clue: 6 of the top 10 U.S. cities in population are found in these 2 states

SOLUTION: california & texas

PROBLEM: Category: 19th CENTURY CRIMES 
Clue: It resulted from the perpetrator's delusion that he was going to be ambassador to France

SOLUTION:
the garfield assassination