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

Ex Input:
What is the smallest country in Central America Costa Rica, Venezuela or El Salvador?

Ex Output:
central america


Ex Input:
Mr Barkis, Edward Murdstone and Tommy Traddles are all characters in which Charles Dickens novel?

Ex Output:
charles dickens


Ex Input:
Born in Argentina in 1942, which pianist and conductor has been has been music director of the Berlin State Opera since 1992, and was music director of the Chicago Symphony Orchestra from 1991 to 2006?

Ex Output:

chicago symphony orchestra