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': 'Renal calculus seen in proteus infection is \nSelect and explain. \nA. Uric acid, B. Xanthine, C. Triple phosphate, D. Calcium', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Urease producing organisms eg :- proteus ,psuedomonas , and staphylococcus , break down urea to produce ammonia and co2.The urine becomes alkaline which promotes formation of struvite calculi ( magnesium ammonium phosphate ) which grow to become staghorn calculi.E coli never forms struvite stones ref :- Bailey and Love 27th edition .chapter 72 . pg no 1406', 'role': 'assistant'}]