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: Anaesthesia
[{'content': 'You are about to perform surgery on a patient with an ASA score of 3 (American society of Anaesthesiologists). What does the score of 3 mean? \nSelect and explain. \nA. The patient has mild systemic disease, but no limitation of activity, B. The patient has severe systemic disease that limits activity but not incapacitating, C. The patient is moribund and not expected to survive 24 hours even with operation, D. The patient has incapacitating systemic disease which poses a threat to life', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ASA score: a) Normal healthy - 1 b) Mild systemic disease, but no limitation of activity - 2 c) Severe systemic disease that limits activity but not incapacitating - 3 d) Incapacitating systemic disease which poses a threat to life - 4 e) Moribund and not expected to survive 24 hours even with operation - 5 Ref: Oxford Handbook of Clinical Specialities, Edition 8, Page 618', 'role': 'assistant'}]