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: Double vision, the perception of two images from a single object, is properly called what?

Answer: double vision

Question: Christopher Eccleston, Kerry Fox and Ewan McGregor played flatmates in which 1994 film?

Answer: christopher eccleston

Question: Which boxer won a 1.8m claim against promotor Frank Warren in March 2009?

Answer:
boxing