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: Medicine
[{'content': 'Average incubation period of AIDS is: March 2011 \nSelect and explain. \nA. 1 year, B. 3 years, C. 5 years, D. 10 years', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. D : 10 years The median interval from infection to the development of symptoms is around 7-10 years, although subgroups of patients exhibit 'fast' or 'slow' rates of progression.", 'role': 'assistant'}]