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': 'Inability to perform any work without discomfort is \nSelect and explain. \nA. NYHA 1, B. NYHA 2, C. NYHA 4, D. NYHA 3', 'role': 'user'}, {'content': 'Answer: C \nExplanation: New York Heart Association (NYHA) Classification\nImportance: Scale used for quantification of degree of functional limitation imposed by Congestive health failure\xa0(CHF)', 'role': 'assistant'}]