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': 'Aspirin in very low doses inhibits the formation of: September 2006 \nSelect and explain. \nA. Cyclooxygenase, B. Thromboxane A2, C. Prostaglandin 12, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: Thromboxane A2', 'role': 'assistant'}]