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
Which of the following amino acids is quickly converted to tyrosine? 
Select and explain. 
A. Arginine, B. Glycine, C. Phenylalanine, D. Leucine
C: Phenylalanine
Answer: C: Phenylalanine 
Explanation: None