This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
Mechanism of aspirin action is 
Select and explain. 
A. Conves inactive plasminogen into active plasmin, B. Inhibits COX and thus thromboxane synthesis, C. Enhances the interaction between antitrombin III and both thrombin and the factors involved in the intrinsic clotting cascade, D. Inhibits the glycoprotein IIb/IIIa complex
B: Inhibits COX and thus thromboxane synthesis
Answer: B: Inhibits COX and thus thromboxane synthesis 
Explanation: Aspirin inhibits the synthesis of thromboxane A2 by irreversible acetylation of the enzyme cyclooxygenase.Other salicylates and nonsteroidal anti-inflammatory drugs also inhibit cyclooxygenase but have a shoer duration of inhibitory action because they cannot acetylate cyclooxygenase; that is, their action is reversible.Katzung 13e pg: 595