instruction:
Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
question:
Who wrote `20,000 Leagues Under The Sea`?
answer:
20,000 leagues under the sea


question:
Christopher Eccleston, Kerry Fox and Ewan McGregor played flatmates in which 1994 film?
answer:
christopher eccleston


question:
Which singer married Bianca Perez-Mora Macias in St Tropez in 1971?
answer:

bianca jagger