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: ANCIENT CITIES 
Clue: It sided with Sparta in the Peloponnesian War, & the Bible includes 2 letters to its Christians

SOLUTION: corinth

PROBLEM: Category: THE 20th CENTURY 
Clue: In the 1940s Franklin Roosevelt coined this term in reference to all the countries allied against the Axis powers

SOLUTION: united nations

PROBLEM: Category: COMMUNICATION 
Clue: A government website says it's "a complete, complex language... said to be the 4th most commonly used" in the U.S.

SOLUTION:
american sign language