This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': 'A 5-year-old child develops fever with rash on first day of fever. Rash disappears after few days and child develops ataxia. Most probable diagnosis? NOT RELATED-MEDICINE \nSelect and explain. \nA. Measles, B. Fifth disease, C. Rocky mountain spotted fever, D. Chickenpox', 'role': 'user'}, {'content': 'Answer: D \nExplanation: .', 'role': 'assistant'}]