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
Chymotrypsin cleaves carbonyl terminal of 
Select and explain. 
A. Phenylalanine, B. Tryptophan, C. Tyrosine, D. All of these
D: All of these
Answer: D: All of these 
Explanation: None