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
Xanthoproteic reaction involves 
Select and explain. 
A. Nitric acid, B. HCl, C. H2SO4, D. Carbolic acid
A: Nitric acid
Answer: A: Nitric acid 
Explanation: Xanthoproteic reaction is method for determination of amount of protein soluble in solution, using concentrated nitric acid.