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
Million-Nasse’s reaction is specific for the amino acid: 
Select and explain. 
A. Tryptophan, B. Tyrosine, C. Phenylalanine, D. Arginine
B: Tyrosine
Answer: B: Tyrosine 
Explanation: Millon’s Test: The phenol group  of phenylalanine and tyrosine containing proteins, when heated with mercuric sulfate in sulfuric acidand sodium nitrite (or, mercurous and mercuric nitrates in nitric acid) form red colored mercury phenolate.
Reference: Vasudevan 7th  ed, pg 31