<prompt> Pepsinogen is activated by ?EnterokinaseEnteropeptidaseHTrypsin  <response>: Ans. is c i.e.,H Pepsin is secreted by chief cells of stomach in an inactive zymogen form called pepsinogen. Acid IF in lumen of stomach conves pepsinogen to active pepsin. Pepsin once formed also attacks pepsinogen producing more pepsin molecules by autocatalysis. 