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

[Q]: Physics. What is the SI unit for amount of substance?
[A]: amount of substance


[Q]: Besides the Caucasus, what mountain range forms the border of Europe and Asia?
[A]: asia


[Q]: Brigitte Bardot originally duetted on and prevented the release of what 1960s song, which later became a hit when she was replaced by Jane Birkin?
[A]:
brigitte bardot