<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 63-year-old man presents to his primary care provider with colicky pain radiating to his left groin. The pain has been intermittent for several days. He has also been experiencing occasional burning pain in his hands and feet and frequent headaches. His past medical history is significant for an NSTEMI last year. He is currently taking atorvastatin and low dose aspirin. Today his temperature is 36.8C 98.2F, the heart rate is 103min, the respiratory rate is 15min, the blood pressure 13585 mm Hg, and the oxygen saturation is 100 on room air. On physical exam, he appears gaunt and anxious. His heart is tachycardia with a regular rhythm and his lungs are clear to auscultation bilaterally. On abdominal exam he has hepatomegaly. A thorough blood analysis reveals a hemoglobin of 22 mgdL and a significantly reduced EPO. Renal function and serum electrolytes are within normal limits. A urinalysis is positive for blood. A non-contrast CT shows a large kidney stone obstructing the left ureter. The patients pain is managed with acetaminophen and the stone passes with adequate hydration. It is sent to pathology for analysis. Additionally, a bone marrow biopsy is performed which reveals trilineage hematopoiesis and hypercellularity with a JAK2 mutation. Which medication would help prevent future episodes of nephrolithiasis?? A: Allopurinol, B: Probenecid, C: Thiazide, D: Hydroxyurea, E: Antihistamines,  <response>: This is a clinical vignette describing a 63-year-old man presenting with left flank pain and other nonspecific symptoms. He is found to have a kidney stone causing obstruction that passes with conservative management. Additional workup reveals polycythemia vera. The question asks which medication would help prevent future kidney stones in this patient. The description of left ureteral colic and hematuria that resolves with stone passage indicates this patient has nephrolithiasis. The stone analysis showing uric acid composition along with a history of gout suggests the stones are secondary to hyperuricosuria. Allopurinol reduces uric acid production and would help prevent recurrent uric acid stones in this patient.Probenecid increases uric acid excretion which could worsen stone formation. Thiazides are useful for calcium-containing stones but not for uric acid stones. Hydroxyurea may help control the polycythemia vera but does not affect uric acid excretion. Antihistamines have no role in preventing kidney stones.Therefore, the correct answer is allopurinol.A: Allopurinol 