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: LETHAL WEAPONS 
Clue: In the largest man-made explosion in history, the USSR detonated a 50-megaton one of these in 1961
answer:
a hydrogen bomb


question:
Category: "BLACK" MOVIES 
Clue: This 1979 Disney sci-fi film starring Maximilian Schell was nominated for an Oscar for Visual Effects
answer:
the black hole


question:
Category: GO WITH THE FLOW 
Clue: The Tigris flows into this gulf
answer:

the persian gulf