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

[Q]: In which war did the Sack of Badajoz takeplace?
[A]: siege of badajoz


[Q]: Which composer was married to Clara Wieck from 1840 until his death in 1856?
[A]: clara schumann


[Q]: To which, position did Joachim Gauck succeed Christian Wulff in spring 2012?
[A]:
joachim gauck