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

[EX Q]: What was the name of country music`s first superstar who died at the age of 29 from drink and drug abuse?
[EX A]: country music

[EX Q]: Which popular animated characters, first seen in 1996 include many different characters including ones called Ash Ketchum, Tracy Sketchit and Gar Oak?
[EX A]: tracy

[EX Q]: Upminster and Ealing Broadway are respectively the eastern and western termini or which London Underground line?
[EX A]:
ealing broadway station