The correct option is B cholecystokinin
Cholecystokinin (in fact it is cholecystokinin pancreozymin) is a hormone which is secreted by small intestine and stimulates pancreas to secrete and release digestive enzymes in pancreatic juice. Secretin causes the release of bicarbonates in the pancreatic juice. Enterokinase is an enzyme that converts trypsinogen (a proenzyme) into trypsin.