This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Antiplatelets and Fibrinolytics, Subject name: Pharmacology
Mechanism of action of Aspirin 
Select and explain. 
A. Inhibit PGI2 formation, B. Inhibit TXA2 formation, C. Stimulate TXA2 formation, D. Stimulate platelet aggregation
B: Inhibit TXA2 formation
Answer: B: Inhibit TXA2 formation 
Explanation: Ans. (b) Inhibit TXA2 formationRef KDT 6th ed. / 609; Katzung 9th ed. / 446Thromboxane helps in platelet aggregation.* TXA2 formation is suppressed at very low doses of aspirin.* Aspirin blocks thromboxane formation by inhibiting COX activity by enzyme COX1 and TX- synthase irreversibly.