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
The commonest enzyme deficiency is of: 
Select and explain. 
A. Glucose-1-phosphatase, B. Glucose-6-phosphatase, C. Carbonic anhydrase, D. Cystathione synthetase
B: Glucose-6-phosphatase
Answer: B: Glucose-6-phosphatase 
Explanation: Glucose-6-phosphatase