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: Which actress played Arwen in the trilogy of films?

Answer: arwen


Question: What was the title of Britney Spears' second album (and the single that was released from it)?

Answer: britney spears


Question: Which pop singer is the mother of Blue Ivy Carter?

Answer:
blue ivy carter