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': 'Urinary stone formed in patients with regional bowel enteritis is \nSelect and explain. \nA. Calcium oxalate, B. Urate, C. Phosphate, D. Cysteine', 'role': 'user'}, {'content': "Answer: A \nExplanation: Calcium oxalate stones are more common in Crohn's patients (regional bowel enteritis)than in the general population because of fat malabsorption. Fat binds to calcium, leaving oxalate free to be absorbed leading to hyperoxaluria and deposition in the kidney, where it can form into stones ref : Bailey 27th edition , chapter 76 , 69 , pg no :- 1406 , 1244", 'role': 'assistant'}]