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: Surgery
[{'content': 'Radio-luscent renal stones are composed of ? \nSelect and explain. \nA. Cysteine, B. Calcium phosphate, C. Uric acid, D. All', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans is i.e., 'c' i.e. Uric acid Pure uric acid stones are radiolucent but uric acid stone usually contains calcium and are opaque.", 'role': 'assistant'}]