This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, 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: In pyloric stenosis vomiting is a prominent feature. Due to vomiting there is loss of gastric HCl which causes metabolic alkalosis.', 'role': 'assistant'}]