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
The most important function of hydrochloric acid in the stomach is: 
Select and explain. 
A. Destruction of bacteria, B. Neutralization of chyme, C. Activation of pepsinogen, D. Stimulation of pancreatic secretion
C: Activation of pepsinogen
Answer: C: Activation of pepsinogen 
Explanation: Functions of HCl are: 

activation of pepsinogen to pepsin by providing acidic medium,
bacteriolytic action and
acidification of chyme which cause release of secretin and cholecystokinin hormones.