Option 1: Pepsin is an enzyme found in the stomach that is responsible for breaking down proteins into smaller peptides.

Option 2: Trypsin is the correct answer. It is produced in the pancreas and acts in the small intestine to further break down peptides into smaller amino acids.

Option 3: Erepsin is an enzyme found in the small intestine that is responsible for the final digestion of peptides into individual amino acids.

Option 4: Enterokinase is an enzyme that activates trypsinogen (the inactive form of trypsin) into trypsin in the small intestine.

The correct answer is option 2, Trypsin. It is primarily responsible for the digestion of proteins into smaller peptides that can be further broken down and absorbed by our bodies.