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': 'For controlling an outbreak of cholera, all of the following measures are recommended except \nSelect and explain. \nA. Mass chemoprophylaxis, B. Proper disposal of excreta, C. Chlorination of water, D. Early detection and management of cases', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]