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.

[EX Q]: Category: STATES' SOUTHWEST CORNERS 
Clue: This state's is just north of the Columbia River
[EX A]: washington

[EX Q]: Category: ELEMENT NAMES 
Clue: Found by Carl Gustav Mosander, terbium is named for Ytterby, a village in this country
[EX A]: sweden

[EX Q]: Category: CLASSIC GAMES 
Clue: Anthony Pratt, a solicitor's clerk, invented this classic whodunit board game
[EX A]:
clue