This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urolithiasis, Subject name: Surgery
[{'content': 'Radiolucent renal stone \nSelect and explain. \nA. Uric acid, B. Calcium oxalate, C. Triple phosphate, D. Calciumphosphate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Uric acidRadiolucent kidney stones are-L.U.XRadio Lucent stones are Uric acid and Xanthine stones', 'role': 'assistant'}]