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

Q: Which singer played Billie Holiday in the 1972 film `Lady Sings The Blues`?

A: lady sings the blues
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Q: In 1864, the Dale Dyke Dam burst while being filled, leading to the death of 240 people in which British city?

A: dale dike reservoir
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Q: Who commanded the RAF Fighter Command during the 'Battle of Britain'?

A:
britain
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