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 consistency, answers should be in all lower cased letters.

Category: NONFICTION 
Clue: This 1988 bestseller was subtitled "From the Big Bang to Black Holes"
a brief history of time

Category: FAMILIAR PHRASES 
Clue: Pool table piece you don't want to be "behind"
the 8 ball

Category: CURRENT MUSIC 
Clue: This celebrity kid wasn't weeping when she hit the charts with "Whip My Hair"

willow smith