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

[EX Q]: Who won a Gold Medal for Britain in the men's 100 metres at the 1992 Summer Olympic Games in Barcelona?
[EX A]: britain

[EX Q]: Created by Alex Raymond, this futuristic character first appeared in 1934. Who is he?
[EX A]: alex raymond

[EX Q]: What ancient empire was led by Xerxes, Cyrus, and Darius?
[EX A]:
darius i