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
Insulin acts on which enzyme is glycolysis : 
Select and explain. 
A. Glucokinase, B. Hexokinase, C. Glucose-6-phosphatase, D. All of the above
A: Glucokinase
Answer: A: Glucokinase 
Explanation: None