This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'The El Tor biotype of vibrio cholerae was first isolated from: \nSelect and explain. \nA. India, B. Egypt, C. Bangladesh, D. Pakistan', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The El Tor biotype was first isolated at the El Tor quarantine station in Egypt in 1905. Ref: Park 21st edition, page 207.', 'role': 'assistant'}]