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: Social & Preventive Medicine
[{'content': "Which of the following better correlates with Sullivan's index: March 2009 \nSelect and explain. \nA. Infant moality rate, B. Life expectancy at the age of one, C. Per capita income, D. Numbers of years lived without disability", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D: Numbers of years lived without', 'role': 'assistant'}]