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

[EX Q]: Which former Portuguese African Colony joined the British Commonwealth in 1995?
[EX A]: commonwealth of nations

[EX Q]: Christian Grey is a character in what recent book trilogy?
[EX A]: christian grey

[EX Q]: What is Africa's second longest river?
[EX A]:
africa