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
A 35-year-old woman has been taking acetylsalicylic acid (aspirin) for ahritis for several years. Her joint pain is reduced this therapy, though the joint destruction with loss of aicular cailage still continues. However, the aspirin therapy temporarily alletes her pain. This pain reduction is primarily the result of diminishing the inflammatory response characterized by: 
Select and explain. 
A. Neutrophil chemotaxis by leukotriene B4, B. Fever resulting from interleukin-1 release, C. Prostaglandin mediated vasodilation, D. Pain resulting from bradykinin generation
C: Prostaglandin mediated vasodilation
Answer: C: Prostaglandin mediated vasodilation 
Explanation: Prostaglandins are produced the cyclooxygenase pathway of arachidonic acid metabolism. Aspirin and nonsteroidal anti-inflammatory drugs block the synthesis of prostaglandins, which can produce pain. NSAID anti-inflammatory activity is mediated chiefly through inhibition of prostaglandin biosynthesis Ref: Furst D.E., Ulrich R.W., Prakash S. (2012). Chapter 36. Nonsteroidal Anti-Inflammatory Drugs, Disease-Modifying Antirheumatic Drugs, Nonopioid Analgesics, & Drugs Used in Gout.