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

In which constellation is the star Deneb?
deneb

Zoey Barkow, Kevin Peyton, Eddie Walzer and Fitch Cooper are all characters in which US television series?
merritt wever

Which actor, (the eighth Doctor Who) played the role just once in a 1996 TV movie?
eighth doctor