instruction:
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.
question:
Category: SUCH GOOD CHEMISTRY 
Clue: A U.S. nuclear weapon using this element, Co, has been termed a doomsday device, as it would wipe out life on Earth
answer:
cobalt


question:
Category: LET'S GET DOWN TO BUSINESS 
Clue: I can get it for you wholesale at this warehouse chain that merged with Price Club in 1993
answer:
costco


question:
Category: CLASSIC GAME SHOW TAGLINES 
Clue: "Caveat emptor.  Let the buyer beware"
answer:

let\'s make a deal