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: Who wrote the 1939 book The Big Sleep?

Answer: the big sleep


Question: Who played boxer James Braddock in the 2005 biopic Cinderella Man?

Answer: james j. braddock


Question: Bartlett, Bosc, d'Anjou and Choke are all types of what?

Answer:
d'anjou