This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Renal physiology, Subject name: Physiology
Rennin is present in 
Select and explain. 
A. Gastric juice, B. Liver, C. Kidney, D. Lung
A: Gastric juice
Answer: A: Gastric juice 
Explanation: Rennin is present in the Gastric juice whereas Renin is related to kidney. Ref: Ganong's review of medical physiology; 24th edition