Answer:
option B. chief cells
Step-by-step explanation:
The inner wall of stomach contain gastric pits. The pits contain certain cells that secretes chemicals. The cheif and parietal cells are present in gastric pits. The Hcl secreted by parietal cells. The hcl is involved in conversion of pepsinogen to pepsin. The pepsinogen is the inactive form and it become activated by hcl. The inactive zymogen (pepsinogen) is released into gastric juice. The chief and mucus cells secrete pepsinogen. The active pepsin is responsible for digesting proteins. Thus, option B is correct.