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

[Q]: Which Chuck Berry song is performed by Marty McFly at the end of the film Back to the Future?
[A]: back to the future


[Q]: What was the name of Chuck Berry`s 1972 hit which gave him his first number one?
[A]: chuck berry


[Q]: Which composer wrote the operas 'The Barber Of Seville' and 'William Tell'?
[A]:
the barber of seville