Secretion of cholecystokinin from the intestinal wall is stimulated by

The correct answer is: fat in the small intestine.

Explanation:

Cholecystokinin, abbreviated to CCK, is a hormone produced in the small intestine that participates in digestion. Its secretion is stimulated by fatty acids in the small intestine (more specifically, in the duodenum) and by the introduction of hydrochloric acid.

Cholecystokinin has the functions to 1) contract the gallbladder so it releases the stored bile into the intestine, and 2) stimulate the secretion of pancreatic juice, which induces satiety.