Answer:
b. cholecystokinin (CCK), an intestinal hormone responsible for gallbladder contraction
Explanation:
Chemical digestion is the process that involves the breakdown of chemical bond that holds food particles together into small parts to nourish the cells in the body. Thus, almost all chemical digestion takes place in the small intestine and enzymes used for the purpose of digestion are usually secreted by the pancreas which enters the small intestine through pancreatic duct. Furthermore, the entrance of digestive enzymes into the small intestine can only occur only when cholecystokinin hormone is secreted which is responsible for digestion of fats and protein.