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': "Glycogen storage disorder due to muscle phosphorylase deficiency \nSelect and explain. \nA. Mcardle's disease, B. Pompe's disease, C. Andersen's disease, D. Tarui's disease", 'role': 'user'}, {'content': 'Answer: A \nExplanation: McArdle&;s disease: type V glycogen storage disease.Due to deficiency of muscle phosphorylase. Incidence 1 out of 1million.Ref: DM Vasudevan, 7th edition, page no: 144', 'role': 'assistant'}]