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

[EX Q]: Who choreographed the ballets Swan Lake and Don Quixote, among others?
[EX A]: don quixote

[EX Q]: Who directed the film Black Swan (in ballet)?
[EX A]: black swan

[EX Q]: The headquarters building of which government agency is known as 'The Doughnut' due to its shape?
[EX A]:
the doughnut