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: Medicine
[{'content': "In Duchenne's muscular dystrophy, which muscle is not involved -a) Gastrocnemiusb) Vastus medialisc) Brachioradialisd) Infraspinatus \nSelect and explain. \nA. c, B. d, C. ab, D. bd", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]