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': 'One DALY signifies: \nSelect and explain. \nA. 1 year of disease free life, B. 1 lost year of healthy life, C. 1 month of bed ridden life, D. None of these', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 1 lost year of healthy life', 'role': 'assistant'}]