TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Dora Maar au Chat and The Weeping Woman are both portraits by which artist of his lover?

SOLUTION: dora maar au chat

PROBLEM: Chris Difford and Glenn Tilbrook founded which band in 1974?

SOLUTION: chris difford

PROBLEM: Dr. Who's companion as played by Billie Piper?

SOLUTION:
billie piper