TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: What's the name of Doctor Who's home planet ?

SOLUTION: doctor who

PROBLEM: Which chemical element is named after the Latin for Copenhagen where it was discovered?

SOLUTION: copenhagen

PROBLEM: The Bernstein and Sondheim song 'Somewhere' was written for which musical?

SOLUTION:
stephen sondheim