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': 'Healthy carriers are present in all except- \nSelect and explain. \nA. Diphtheria, B. Pertussis, C. Typhoid, D. Cholera', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Healthy carriers emerge from sub clinical cases. They are victims of sub clinical cases who have developed carrier state without suffering from overt diseases, but are nevertheless shedding the disease agent. Eg polio, cholera, meningococcal meningitis, salmonellosis, and diphtheria', 'role': 'assistant'}]