The correct option is C a - ii, b - i, c - iv, d - iii
a) Secretin -Stimulates the secretion of water and bicarbonates in pancreatic juice (It is secreted by the S cells of the duodenum and regulates the secretion of Pancreas,liver and stomach
b)Gastrin - stimulates secretion of gastric glands (It stimulates the secretion of HCl in the stomach
c)Cholecystokinin - stimulates secretion of pancreatic enzymes (it is released by the endocrine cells of the small intestine to aid digestion of proteins and fats in the chyme)
d) Gastric inhibitory polypeptide - inhibits gastric secretion and motility (prevents secretion of HCl in the stomach)
So, the correct answer is a - ii, b - i, c - iv, d - iii'