Q: Determine the topic of the question. Question: "how many users do twitter have?" Topic:
A: Twitter

Q: Determine the topic of the question. Question: "who owns land rover?" Topic:
A: Land Rover

Q: Determine the topic of the question. Question: "how many grape farms in united states?" Topic:
A: Agriculture in the United States

Q: Determine the topic of the question. Question: "what zones are tropical?" Topic:
A:
Tropics