The correct option is D Trypsin
The mucus protects the inner lining of the stomach from the action of the acid under normal conditions. Mucus is released by the mucus secreting cells in the stomach. The gastric glands release hydrochloric acid and a protein digesting enzyme called Pepsin. The hydrochloric acid creates an acidic medium which facilitates the action of the enzyme pepsin. Pepsin later helps convert proteins to peptones. Thus mucus, HCl and pepsinogen are secreted by the stomach during digestion. Trypsin is secreted in the pancreas and thus is not secreted by the stomach during digestion.