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: ONE-WORD BEST PICTURE OSCAR WINNERS 
Clue: A middle name in Latin
amadeus

Category: ACTORS ON STAGE 
Clue: Tyne Daly & Angela Lansbury won Tonys for playing Mama Rose in this musical, but Ethel Merman didn't
gypsy

Category: PHYSICS 
Clue: After trying to measure this with signals between himself & an assistant, Galileo decided it was infinite

the speed of light