TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Aldebaran is the brightest star in which constellation?

SOLUTION: aldebaran

PROBLEM: Who directed the film Black Swan (in ballet)?

SOLUTION: black swan

PROBLEM: In which book did Aunt Ada Doom see 'something nasty in the woodshed'?

SOLUTION:
aunt ada doom