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.

Example Input: Category: THE ENVIRONMENT 
Clue: This word means catching an unsustainably high number of tuna & cod
Example Output: overfishing

Example Input: Category: PARTICLE PHYSICS 
Clue: To get an element's mass number, add its protons & these
Example Output: neutrons

Example Input: Category: ROCK BAND INITIALS 
Clue: Fans popularly refer to them as GN'R
Example Output:
guns n\' roses