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: Surgery
[{'content': "Duchenne's muscular dystrophy affects which group of muscle s commonly: September 2009 \nSelect and explain. \nA. Calf muscles, B. Shoulder muscles, C. Forearm muscles, D. Respiaory muscles", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Calf Muscles', 'role': 'assistant'}]