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: Biochemistry
[{'content': "Muscle phosphorylase deficiency leads to which glycogen storage disorder \nSelect and explain. \nA. Hers disease, B. McArdles disease, C. Cori's disease, D. Andersen disease", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Muscle phosphorylase deficiency leads to McArdle\'s disease. (Mnemonic "M for M\') which is characterised by poor exercise tolerance, Muscle glycogen being abnormally high and blood lactate level very low after exercise.\nMnemonic\n\nHeri\'s disease - Hepatic phosphorylase\nAndersen disease - Branching enzyme\nCori\'s disease - Debranching enzyme.', 'role': 'assistant'}]