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
Which of the following irrevbersibly inhibits cyclooxygenase 
Select and explain. 
A. Celcoxib, B. Acetaminophen, C. Aspirin, D. Indomethacin
C: Aspirin
Answer: C: Aspirin 
Explanation: Aspirin