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

[Q]: What book was written by Alexandre Dumas about Edmond Dantes' imprisonment in the Chateau d'If?
[A]: alexandre dumas

[Q]: Which English king was the son of Edward, the Black Prince?
[A]: edward, the black prince

[Q]: The group 'Abba' was formed in which European capital city in 1971?
[A]:
abba