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

[EX Q]: Cilantro is the leaf of which herb?
[EX A]: cilantro

[EX Q]: Which 20th century British prime minister had the longest surname ?
[EX A]: prime minister of the united kingdom

[EX Q]: Who was Britain's first ever Labour prime minister in 1924?
[EX A]:
britain