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: MONARCHIES 
Clue: 1 of the 2 largely German-speaking monarchies in the world; they're about 250 miles apart

Answer: liechtenstein & luxembourg


Question: Category: PLAGUES & PESTILENCE 
Clue: Having first escaped from a South American research lab in 1957, they became a threat to the U.S. in 1990

Answer: killer bees


Question: Category: ADVERTISING 
Clue: This product's "Whole Thing" commercial is in the Clio Hall of Fame

Answer:
alka-seltzer