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 legal drama starring Martin Shaw ran for six series on BBC TV from 2001?

Answer: martin shaw

Question: 'Highway 61 Revisited' and 'Blood On The Tracks' were both albums released by which popular singer?

Answer: highway 61 revisited

Question: Bella Wilfer is a character in which of Charles Dickens' books?

Answer:
charles dickens