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: Medicine
[{'content': 'All of the follwing types of Renal Stones are Radiopaque, Except: \nSelect and explain. \nA. Oxalate, B. Uric Acid, C. Cystine, D. Mixed', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Uric Acid): Uric acid stones are characteristically Radiolucent', 'role': 'assistant'}]