Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

Q: What is the title of the four-episode special of 'Doctor Who', made for the Red Nose Day telethon in the UK, broadcast in March 1999?

A: doctor who
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Q: What horse won the 2009 Grand National?

A: 2009 grand national
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Q: The novel, Birdsong, by Sebastian Faulks, is mainly set during which war?

A:
birdsong
****