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': 'A two year old unimmunized child presents to a primary health centre with fever since 5 days. Mother also gives a history of rash staing behind ear-pinna a day before coming to OPD. On examination, child is having running nose and congested eyes. Most probable diagnosis is:- \nSelect and explain. \nA. Rubella, B. Mumps, C. Measles, D. Chickenpox', 'role': 'user'}, {'content': 'Answer: C \nExplanation: MEASLES Incubation period :10-14 days Causative agent: RNA paramyxovirus Source of infection: cases Period of communicability: 4 days before & 4 days after the appearance of rash Measles has no second attacks Pathognomic clinical feature of measles: koplik spots Other clinical features: coryza, fever, red eyes, cough MC complication of measles in young children: otitis media.', 'role': 'assistant'}]