TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Who played Bonnie in the 1967 film 'Bonnie And Clyde'?

SOLUTION: bonnie and clyde

PROBLEM: What horse won the 2009 Grand National?

SOLUTION: 2009 grand national

PROBLEM: Double vision, the perception of two images from a single object, is properly called what?

SOLUTION:
double vision