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': "Sullivan's index measures - \nSelect and explain. \nA. Moality, B. Morbidty, C. Infectivity, D. Disability", 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Disability", 'role': 'assistant'}]