This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Enzyme Kinetics, Subject name: Biochemistry
[{'content': 'Which of the following enzymes is stable at acidic pH: \nSelect and explain. \nA. Pepsin, B. Trypsin, C. Chymotrypsin, D. Carboxypeptidase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. PepsinPepsin is formed when pepsinogen is activated by hydrochloric acid in the stomach. The optimum pH for pepsin action is 1.6 to 3.2.', 'role': 'assistant'}]