This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Structure and function of protein, Subject name: Biochemistry
All have aromatic rings except 
Select and explain. 
A. Phenylalanine, B. Tyrosine, C. Tryptophan, D. Lysine
D: Lysine
Answer: D: Lysine 
Explanation: Aromatic amino acids are Tyrosine, tryptophan, and phenylalanine.Ref: Textbook of medical biochemistry, MN Chatterji, 8th edition, page no: 78