This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
[{'content': 'cardiomyopathy absent in ? \nSelect and explain. \nA. DMD, B. Becker Dystrophy, C. Myotonic Dystrophy, D. Myasthenia Gravis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ref harrisons21st ed', 'role': 'assistant'}]