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

[EX Q]: I which European city will you find 'Dam Square'?
[EX A]: dam square

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

[EX Q]: Who painted Diana and Actaeon, acquired for the nation by the National Gallery and National Gallery of Scotland in 2009?
[EX A]:
diana and actaeon