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: Surgery
Highest concentration of potassium is seen in - 
Select and explain. 
A. Jejunum, B. ileum, C. Duodenum, D. Colon
D: Colon
Answer: D: Colon 
Explanation: • Maximum K+ concentration: Colon (30 mEq/L) >Saliva (25 mEq/L)