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

[Q]: Which popular Doctor Who villains, it was revealed in 2011, are to be given 'a rest' by scriptwriters?
[A]: doctor who


[Q]: Aragon and Castile joined to form which country?
[A]: aragon


[Q]: Which is the largest lake in Africa?
[A]:
africa