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: Where is Charles Darwin buried?

Answer: charles darwin


Question: Ashgabat is the capital of which country, a former Soviet republic in Asia?

Answer: ashgabat


Question: Edward Norton, EricBana and Mark Ruffalo have all played which character on film?

Answer:
mark ruffalo