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: Physiology
In the stomach, H+ ions are secreted in exchange for 
Select and explain. 
A. Na+, B. K+, C. Ca+, D. Cl-
B: K+
Answer: B: K+ 
Explanation: H+-K+ ATPase is present in stomach.