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

[Q]: Which country is currently ruled by the Chakri dynasty that has been in power since 1782?
[A]: chakri dynasty


[Q]: The film The Curious Case of Benjamin Button, starring Brad Pitt, is based on a short story by whom?
[A]: the curious case of benjamin button


[Q]: Washington DC National Airport has been named in honour of which US President?
[A]:
ronald reagan washington national airport