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: 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
cobalt

Category: CURRENT EXPRESSIONS 
Clue: If you're engaging in wishful thinking, you may want to perform this type of "check"
a reality check

Category: ADDRESS ME 
Clue: Holly Robinson & Peter DeLuise were youthful cops on the show named for this address

21 jump street