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 plays Isobel Crawley in the UK television series 'Downton Abbey'?

SOLUTION: downton abbey

PROBLEM: Ride of the Valkyries is the official quick march of which branch of the British Army?

SOLUTION: british army

PROBLEM: Which film, for which Carey Mulligan won a Best Actress BAFTA, is based on the memoirs of journalist Lynn Barber?

SOLUTION:
lynn barber