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

What was the first Apollo mission to leave Earth orbit and orbit the moon, in 1968?
apollo

Allopurinol is typically prescribed for which illness?
allopurinol

Who plays Daphne in the 2002 film 'Scooby-Doo'?

scooby-doo