This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Amino Acid Metabolic Disorder, Subject name: Biochemistry
Phenylketonuria is due to deficiency of - 
Select and explain. 
A. Phenylalanine transaminase, B. Phenylalanine hydroxylase, C. Tyrosine transaminase, D. Tyrosine hydroxylase
B: Phenylalanine hydroxylase
Answer: B: Phenylalanine hydroxylase 
Explanation: Ans. is 'b' i.e., Phenylalanine hydroxylase o Repeat from previous session