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

[Q]: Which late 17th and early 18th century British architect designed Brighton Pavilion, Marble Arch, and the plan for London's Regents Park?
[A]: royal pavilion


[Q]: Which sprinter lit the Olympic flame at the 2000 Summer Olympic Games in Australia?
[A]: 2000 summer olympics


[Q]: Who stabbed 'Carmen' in the opera of the same name?
[A]:
carmen