Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
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Question: What is the smallest country in Central America Costa Rica, Venezuela or El Salvador?

Answer: central america


Question: Double vision, the perception of two images from a single object, is properly called what?

Answer: double vision


Question: Charlotte of Mecklenburg-Strelitz was the wife of which King of Great Britain?

Answer:
charlotte of mecklenburg-strelitz