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.
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Question: Category: WORLD LEADERS 
Clue: After overthrowing Milton Obote in 1971, he had some 300,000 people killed

Answer: idi amin


Question: Category: CLASSICAL MYTHOLOGY 
Clue: Some say this underworld canine has serpents entwined around his multiple necks

Answer: cerberus


Question: Category: IT'S NOT EASY BEING TWEEN 
Clue: Tweens watching this young man's video "Baby" on YouTube helped it to a record 260 million views as of summer 2010

Answer:
justin bieber