This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney & Ureturs, Subject name: Surgery
[{'content': 'Stones that are common with infection is: \nSelect and explain. \nA. Struvite, B. Xanthine stone, C. Cysteine stone, D. Calcium oxalate stones', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) StruviteRef: Campbell Urology 1194* Struvite stones (Magnesium Ammonium Phosphate) occur only in association with urinary infection by urea -splitting bacteria. Proteus mirabilis the most common organism associated with infection.', 'role': 'assistant'}]