Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

Q: What is the only nation state of the Commonwealth of Nations on the mainland of South America?

A: commonwealth of nations
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Q: Who composed 'Eine Kleine Nachtmusik' in the 18th Century?

A: eine kleine nachtmusik
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Q: Which horse won the 2009 Cheltenham Gold Cup?

A:
2009 cheltenham gold cup
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