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 film The Curious Case of Benjamin Button, starring Brad Pitt, is based on a short story by whom?

Answer: the curious case of benjamin button


Question: What currency is used on Christmas Island?

Answer: christmas island


Question: Drowning Girl is one of the notable works of which 20th century artist?

Answer:
drowning girl