This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid and electrolytes, Subject name: Medicine
[{'content': "Which of the following doesn't cause metabolic acidosis- \nSelect and explain. \nA. Pyloric stenosis, B. Renal failure, C. Ureterosigmoidostomy, D. Pancreatic Fistula", 'role': 'user'}, {'content': "Answer: A \nExplanation: Uretrosigmoidostomy and pancreatic fistula causes non anion gap metabolic acidosis, whereas renal failure causes high anion gap acidosis. (Ref: Harrison's principles of internal medicine,19E pg 320)", 'role': 'assistant'}]