Parietal cells (also called oxyntic cells) are the stomach epithelium cells which secrete gastric acid.
Stomach acid does not digest protein. Rather, it activates an enzyme called pepsinogen which then becomes pepsin that is secreted by the stomach wall. This enzyme is only active within the pH range of 3.0 to 5.0 and requires the acid to maintain that pH.
if reqired amount of HCl is not prodced then proteins will not be adequately hydrolysed by pepsin to protesoses and peptones
Answer : (b)