This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mechanisms of Enzyme Action, Subject name: Biochemistry
[{'content': 'Chymotrypsinogen is a \nSelect and explain. \nA. Zymogen, B. Carboxypeptidase, C. Transaminase, D. Elastase', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e. Zymogen * Proteolytic digestive enzymes known as proteases have two main classes depending on specificity for the amino acids forming the peptide bond to be hydrolysed.", 'role': 'assistant'}]