This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concept of health and disease, Subject name: Social & Preventive Medicine
[{'content': "The expectation of life, free of disability is known as \nSelect and explain. \nA. Smith's Index, B. Sullivan's Index, C. Life Index, D. Pearl Index", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Sullivan&;s index or disability-free life expectancy or active life expectancy is the average number of years an individual is expected to live free of disability if the current pattern of moality and disability continue to apply.Park 23e pg:26', 'role': 'assistant'}]