This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
[{'content': 'Most common renal stone is \nSelect and explain. \nA. Triple phosphate, B. Calcium oxalate, C. Uric acid, D. Salicylate', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Calcium oxalate stones - 60% Phosphate stones( hydroxyapatite and brushite) - 22% Uric acid stones -7 % ,struvite 7%.Cystine stones - 2% Reference : Campbell and Walsh urology 11th edition , chapter 51 , pg no 1181', 'role': 'assistant'}]