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.

Category: STATES' SOUTHWEST CORNERS 
Clue: This state's is just north of the Columbia River
washington

Category: 10 
Clue: This teenage tennis goddess is often escorted by older Russian hockey players
anna kournikova

Category: THE NIGHTTIME SKY 
Clue: As seen from the Earth, the brightest star excluding the sun is this "Dog Star"

sirius