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.

Q: Category: FICTIONAL BATTLES & WARS 
Clue: Juan Rico joins the mobile infantry to fight in the war against the invading alien "bugs" in this Heinlein novel

A: starship troopers
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Q: Category: LOOK OUT "BELL"OW 
Clue: As one word, it's a plant also called deadly nightshade; as 2 words, a Stevie Nicks album

A: belladonna/"bella donna"
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Q: Category: BRITISH MONARCHS 
Clue: The IV of his name, in 1830 he became the oldest to ascend the throne

A:
william
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