Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

[EX Q]: Who wrote the 1939 book The Big Sleep?
[EX A]: the big sleep

[EX Q]: Established in 1919, which is the world's oldest surviving airline?
[EX A]: airline

[EX Q]: Which US actor appeared in the films 'Ironweed', 'The Pledge' and 'Easy Rider'?
[EX A]:
easy rider