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
Enzyme inhibited by insulin is 
Select and explain. 
A. Glucokinase, B. PFK-1, C. Glycogen phosphorylase, D. Glycogen synthase
C: Glycogen phosphorylase
Answer: C: Glycogen phosphorylase 
Explanation: 3. Hypoglycemic Effect of INSULINE - i. Insulin lowers the blood glucose level by promoting utilization and storage. ii. Gluconeogenesis is inhibited by insulin by repressing the key enzymes, pyruvate carboxylase (PC) phosphoenol pyruvate carboxykinase (PEPCK) and glucose-6- phosphatase. iii. Insulin inhibits glycogenolysis by oring the inactivation of glycogen phosphorylase and inhibiting glucose-6-phosphatase. The net effect of all these three mechanisms, blood glucose level is lowered. REF: DM VASUDEVAN TEXTBOOK OF BIOCHEMISTRY, EIGHTH EDITION,PG.NO.,167.