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
Enzymes in glycogen metabolism 
Select and explain. 
A. Phosphorylase a, B. Phosphorylase b, C. Glycogen Synthase II, D. Glycogen Synthase C
A: Phosphorylase a
Answer: A: Phosphorylase a 
Explanation: The liver phosphorylase-b is the inactive form. It becomes active on phosphorylation. The active enzyme is denoted as phosphorylase-a.Ref: DM Vasudevan, page no: 127