This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anatomy
[{'content': 'All are examples of competitive enzyme blockage except \nSelect and explain. \nA. Cyclooxygenase by Aspirin, B. Thymidylate synthase by 5-FU, C. Coagulation by Dicumarol, D. DHFR by Methotrexate', 'role': 'user'}, {'content': "Answer: A \nExplanation: Kinetics of enzyme inhibition Competitive inhibitionNon competitive inhibitionKm Increased No change V max No change Decreased Significance Drug action Toxicological (Refer: Harper's Illustrated Biochemistry, 26th edition, pg no: 67-68)", 'role': 'assistant'}]