This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid and electrolytes, Subject name: Medicine
The concentration of sodium ion is least in the - 
Select and explain. 
A. Small intestinal juice, B. Bile, C. Gastric juice, D. Pancreatic juice
C: Gastric juice
Answer: C: Gastric juice 
Explanation: primary gastric juice contains Na+ in a concentration of 3-5 mEq/l makes it possible that the secreted volume originates from some sodium-containing compament Ref Davidson 23rd edition pg 365