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: Pharmacology
[{'content': 'Among NSAIDs aspirin is unique because it : \nSelect and explain. \nA. Irreversibly inhibits its target enzyme, B. Reduces the risk of colon cancer, C. Reduces fever, D. Selectively inhibits COX-2 enzyme', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]