This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable Diseases, Subject name: Social & Preventive Medicine
[{'content': 'Healthy carriers are found in all EXCEPT \nSelect and explain. \nA. Poliomyelitis, B. Measles, C. Diphtheria, D. Salmonellosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B. i.e. (Measles) (90 - Park 19th) (91 - Park 20th)Carriers-classifications Incubatory carriers - Measles, mumps, polio, pertussis, influenza, diphtheria and Hepatitis - B Convalescent carriers - Typhoidfever, dysentery, cholera, diphtheria, and whooping cough Healthy carriers - Poliomyelitis*, Cholera, meningococcal meningitis, salmonellosis and diphtheria* Chronic carrier - Typhoidfever, hepatitisB, dysentery, cerebro- spinal meningitis, malaria, gonorrhoea', 'role': 'assistant'}]