This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal tract, Subject name: Pediatrics
Which electrolyte should be replenished in hyperophic pyloric stenosis ? 
Select and explain. 
A. Sodium, B. Hydrogen, C. Chloride, D. Bicarbonate
C: Chloride
Answer: C: Chloride 
Explanation: Hypochloremic, hypokalemic metabolic alkalosis is the classic electrolyte and acid-base imbalance of pyloric stenosis. This prolonged vomiting causes progressive loss of fluids rich in hydrochloric acid, which causes the kidneys to retain hydrogen ions in or of potassium. Reference: GHAI Essential pediatrics, 8th edition