This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Prostaglandins, Subject name: Pharmacology
[{'content': 'Ibuprofen acts by inhibiting:(1994) \nSelect and explain. \nA. Lipo oxygenase, B. Cyclo oxygenase, C. Resetting the hypothalamic thermostat, D. Increases the pain threshold', 'role': 'user'}, {'content': 'Answer: B \nExplanation: bRef: KDT, 5th ed, p. 176, 158 & 4th ed, p. 459, 460', 'role': 'assistant'}]