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]: Who wrote the novel 'Brideshead Revisited'?
[A]: brideshead revisited


[Q]: Where is David Cameron's Oxfordshire constituency?
[A]:
david cameron