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
Which of the following doesn't cause metabolic acidosis - 
Select and explain. 
A. Pyloric stenosis, B. Renal failure, C. Ureterosigmoidostomy, D. Pancreatic Fistula
A: Pyloric stenosis
Answer: A: Pyloric stenosis 
Explanation: In pyloric stenosis vomiting is a prominent feature. Due to vomiting there is loss of gastric HCl which causes metabolic alkalosis.