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: Radiology
[{'content': 'Radio opaque stone is \nSelect and explain. \nA. Uric acid stone, B. Triamterene, C. Struvite, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Radio opaque stones\xa0- Cystine, struvite, calcium oxalate, calcium phosphate.', 'role': 'assistant'}]