TASK DEFINITION: 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.
PROBLEM: Category: MOZART & FRIENDS 
Clue: Mozart wrote a lovely motet for Venanzio Rauzzini, one of these specially treated singers

SOLUTION: a castrato

PROBLEM: Category: EXPRESSIONS 
Clue: This positive expression used since the 1940s promotes a type of stove

SOLUTION: "now you\'re cooking with gas"

PROBLEM: Category: ELIZABETH TAYLOR FILMS 
Clue: This 1963 epic included 79 sets & 26,000 costumes

SOLUTION:
cleopatra