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
Allopurinol is used in the treatment of: 
Select and explain. 
A. Osteoahritis, B. Gout, C. Rheumatoid Ahritis, D. Ankylosing spondylitis
B: Gout
Answer: B: Gout 
Explanation: Allopurinol a xanthine oxidase inhibitor is used in the treatment of gout. By inhibiting xanthine oxidase it reduces uric acid synthesis. Ref: Essentials of Medical Pharmacology By KD Tripathi, 5th Edition, Page 191 - 2.