instruction:
Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
question:
In which Indian city is Eden Gardens, the second largest test cricket ground in the world?
answer:
eden gardens


question:
What was the last silent film in which Chaplin's little tramp appeared?
answer:
chaplin


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

a. j. cronin