This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
True about Rx of Phenylketonuria 
Select and explain. 
A. Limiting the substrate for deficient enzyme, B. Giving the missing amino acids by diet, C. Gene therapy can be successfully used, D. Child should refrain from milk.
A: Limiting the substrate for deficient enzyme
Answer: A: Limiting the substrate for deficient enzyme 
Explanation: .