This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
In a person suffering from phenyl ketonuria, which of the following should be restricted in diet? 
Select and explain. 
A. Fat, B. Protein, C. Glycine, D. Glutamate
B: Protein
Answer: B: Protein 
Explanation: Phenylalanine is an essential amino acid. Deficiency of Pheny alanine hydroxlase os cause for the phenylketonuia. Early detection is very impant. About 5 units of IQ are lost for each 10-week delay in staing the treatment. The treatment is to provide a diet containing low phenylalanine.Food based on tapioca 9cassava0 will have low phenyl alanine content. The special diet is to be continued during the first decade of life. REF :DM VASUDEVAN TEXTBOOK ;7th EDITION;Page no ;237.