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: AFI's TOP MOVIE QUOTES 
Clue: Prizefighter Roger Donoghue was Marlon Brando's trainer for "On the Waterfront" & inspired this line on the AFI list
\"i coulda been a contender\"