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

[Q]: Which group of the 1970's featured Tony Iommi on guitar, Geezer Butler on bass and Bill Ward on drums?
[A]: geezer butler


[Q]: Billy the Kid was a native of which US state?
[A]: billy


[Q]: Who replaced George Entwistle to become the present Director General of the BBC in April 2013?
[A]:
director-general of the bbc