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: FUNNY WESTERNS 
Clue: Gabby Hayes added comic relief to many of this singing cowboy's films including "My Pal Trigger"
roy rogers

Category: SCIENCE 
Clue: This yellow element is found in gunpowder & matches & is used in vulcanizing rubber
sulphur

Category: "T" TIME 
Clue: Dipsy is the green one of these characters on PBS

a teletubby