This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autacoids, Subject name: Pharmacology
Allopurinol specifically inhibits which enzyme? 
Select and explain. 
A. Xanthine oxidase, B. Arginase, C. Carbamoyl transferase, D. Urease
A: Xanthine oxidase
Answer: A: Xanthine oxidase 
Explanation: ESSENTIALS OF MEDICAL PHARMACOLOGY;7TH EDITION;KD TRIPATHI;PAGE NO 216