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: ROCKS & MINERALS 
Clue: A mixture containing antimony is sprayed on canvas to render it this
fireproof

Category: SHADES OF GREEN 
Clue: Introduced in 1993, the Crayola color named for this stalk veggie is more popular with kids than the real thing
asparagus

Category: THE MODEL T 
Clue: The 1910 T featured a rear seat nicknamed for this relative acquired through marriage

"mother-in-law seat"