This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Crystal Ahropathy, Subject name: Medicine
Which is the best treatment for an over-producer in chronic gout with kidney impairment? 
Select and explain. 
A. Allopurinol, B. Febuxostat, C. Uricase, D. Benzbromarone
B: Febuxostat
Answer: B: Febuxostat 
Explanation: Febuxostat, a non-purine selective inhibitor of xanthine oxidase, is a potential alternative to allopurinol in patients with gout. Febuxostat is administered orally and is metabolized mainly in the liver. In contrast, allopurinol and its metabolites are excreted primarily by the kidney. Therefore, febuxostat can be used in patients with renal impairment with no dosage adjustment.