This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc., Subject name: Medicine
[{'content': 'Mainly cholecystokinin is secreted by: \nSelect and explain. \nA. Duodenum, B. Pancreas, C. Gallbladder, D. Ileum', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Release of cholecystokinin (CCK) from the duodenum and proximal jejunum is triggered by long-chain fatty acids, ceain essential amino acids (tryptophan, phenylalanine, valine, methionine), and gastric acid itself. CCK evokes an enzyme-rich secretion from acinar cells in the pancreas.', 'role': 'assistant'}]