This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
[{'content': "Enzyme deficiency in McArdle's syndrome? \nSelect and explain. \nA. Acid maltase, B. Muscle phosphorylase, C. Liver debranching enzyme, D. Branching enzyme", 'role': 'user'}, {'content': "Answer: B \nExplanation: Type name Enzyme Deficiency Clinical Features V Myophosphorylase deficiency, McArdle's syndrome Muscle phosphorylase Poor exercise tolerance Muscle glycogen abnormally high (2.5%-4%) Blood lactate very low after exercise Reference: Harper; 30th edition; Table: 18-2; Page no: 179", 'role': 'assistant'}]