This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory Infections, Subject name: Social & Preventive Medicine
[{'content': 'Subacute Sclerosing Pan Encephalitis (SSPE) is a complication of: \nSelect and explain. \nA. Measles, B. Mumps, C. Rubella, D. Chicken pox', 'role': 'user'}, {'content': "Answer: A \nExplanation: Measles: Cause : RNA paramyxovirus. Incubation period: 10-14 days. Source of infection: Cases . Mode of transmission : Respiratory / air droplets. Period of communicability : 4 days before & 5 days after rash. Pathognomic clinical feature : Koplik spot . Clinical feature : Retro-auricular origin of rash. MC complication : Serous otitis media. Subacute sclerosing pan encephalitis is a rare,late complication of measles - Aka 'dawson's disease', Dawson's encephalitis. Vaccine : Live attenuated ; Edmonsten zagreb strain.", 'role': 'assistant'}]