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: C PLUS
Clue: C plus a cry of pain equals this, a sofa
couch

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: STUPID ANSWERS
Clue: Family of trees on which you'd fine pine cones
pine trees