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

Ex Input:
Chris Martin is the lead singer with which band who had several hits in the 2000s?

Ex Output:
chris martin

Ex Input:
Who was the only boxer to win a world title without ever having a manager?

Ex Output:
boxing

Ex Input:
In the TV series 'Pennies From Heaven' who played the character Arthur Parker?

Ex Output:
arthur parker