This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Myasthenia Gravis and Muscular dystrophy, Subject name: Medicine
[{'content': 'What is not useful for diagnosis of myasthenia gravis? \nSelect and explain. \nA. AChR antibodies, B. Voltage gated calcium channel antibodies, C. Muscle-specific kinase antibodies, D. Edrophonium test', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Voltage-gated calcium channel antibodies are used for diagnosis of Lambe Eaton syndrome. Choices A, C,and D are used for diagnosis of M. Gravis.', 'role': 'assistant'}]