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

Ex Input:
Which novel by A J Cronin is credited with laying down the foundation in Great Britain for the introduction of the National Health Service?

Ex Output:
a. j. cronin

Ex Input:
Where is Charles Darwin buried?

Ex Output:
charles darwin

Ex Input:
Which popular Doctor Who villains, it was revealed in 2011, are to be given 'a rest' by scriptwriters?

Ex Output:
doctor who