This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
Features of pyloric stenosis 
Select and explain. 
A. Hypokalemic alkalosis, B. Peristalsis right to left, C. Commonly caused by carcinoma stomach, D. Retention vomiting present
A: Hypokalemic alkalosis
Answer: A: Hypokalemic alkalosis 
Explanation: Because of vomiting-hypochloremia hyponatremia, hypocalcemia, hypomagnesemia alkalosis occurs. Reference: SRB edition:5th page no: 829