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

[Q]: Which is the only Avril Lavigne song to have reached No.1 in the US Billboard Chart?
[A]: avril lavigne


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


[Q]: Who was the wife of Zeus and the mother of Ares?
[A]:
zeus