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: The song Don't Rain On My Parade features in which musical?

Answer: don't rain on my parade

Question: Which exponent of Brit Art created works involving a bed, a tent and a beach hut?

Answer: young british artists

Question: Which river flows from northern Moscow to the Caspian Sea?

Answer:
caspian sea