Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
--------
Question: Who played boxer James Braddock in the 2005 biopic Cinderella Man?

Answer: james j. braddock

Question: Where is David Cameron's Oxfordshire constituency?

Answer: david cameron

Question: Brigadier Lethridge-Stewart belonged to which military organisation in the Dr Who series?

Answer:
doctor who