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': 'Positive indicator of health ? \nSelect and explain. \nA. IMR, B. Child moality rate, C. MMR, D. Life expectancy', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Life expectancy", 'role': 'assistant'}]