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': 'What is Sanchol? \nSelect and explain. \nA. Hormonal contraceptive, B. Cholera Vaccine, C. Nutritional supplement, D. Pesticide', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Sanchol and MORCVAX are bivalent oral cholera vaccines based on serogroups O1 and O139. Ref: Park 21st edition, page 211.', 'role': 'assistant'}]