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: OPENING LINES OF SHAKESPEARE 
Clue: "Now is the winter of our discontent made glorious summer by this sun of York"
richard iii

Category: YOU'RE AN ANIMAL 
Clue: The plains variety of this animal has gray markings that are known as shadow stripes
a zebra

Category: ROBIN 
Clue: He's starred in 2 "Good" movies: "Good Morning, Vietnam" & "Good Will Hunting"

robin williams