TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Which boxer was nicknames `The Brown Bomber`?

SOLUTION: boxing

PROBLEM: Who is the current Australian prime minister ?

SOLUTION: australia

PROBLEM: Who wrote Zen and the Art of Motorcycle Maintenance?

SOLUTION:
zen and the art of motorcycle maintenance