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.

[Q]: Category: WOMEN WRITERS 
Clue: Mary Chesnut's take on this U.S. war was part of a Ken Burns TV documentary
[A]: the civil war


[Q]: Category: WORLD CAPITALS 
Clue: This capital city of 113,000 is the closest national capital to the Arctic Circle
[A]: reykjavík


[Q]: Category: "C.C." SENOR! 
Clue: Chalk is a naturally occurring form of this compound whose chemical formula is CaCO3
[A]:
calcium carbonate