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

[EX Q]: Who played the character Gene Hunt in the UK TV series 'Life on Mars' and 'Ashes to Ashes'?
[EX A]: life on mars

[EX Q]: In which city will the 2014 Tour de France begin?
[EX A]: 2014 tour de france

[EX Q]: A live episode of which TV soap opera was broadcast on BBC One on 19 February 2010, to celebrate 25 years since the broadcast of the first episode?
[EX A]:
bbc one