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: Pediatrics
Enzyme deficient is Von Gierke disease is 
Select and explain. 
A. Acid maltase, B. Alpha 1, 4 glucosidase, C. Glucose phosphorylase, D. Glucose 6 - phosphatase
D: Glucose 6 - phosphatase
Answer: D: Glucose 6 - phosphatase 
Explanation: Enzyme deficient in Von Gierke disease is Glucose 6 - phosphatase.