instruction:
Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
question:
Where is David Cameron's Oxfordshire constituency?
answer:
david cameron


question:
Which major river has its source at the confluence of the rivers Brigach and Breg in the Black Forest?
answer:
breg


question:
Key Largo, Key West, Plantation Key and Big Pine Key are islands of the coast of are part of which US state?
answer:

dry tortugas