instruction:
Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
question:
Which British composer wrote the music used as the theme for Desert Island Discs He also wrote the Dambusters march and the Knightsbridge march.?
answer:
the dam busters

question:
Eden Park staged some of the 2011 Rugby World Cup matches, in which city can it be found?
answer:
eden park

question:
Who became Archbishop of Canterbury in February 2003?
answer:
archbishop of canterbury