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 Bryce Canyon and Zion National Parks are in which US state?

Answer: bryce canyon national park


Question: Mr Barkis, Edward Murdstone and Tommy Traddles are all characters in which Charles Dickens novel?

Answer: charles dickens


Question: Which author was married to Catherine Hogarth?

Answer:
catherine dickens