This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'Motilin is secreted by cells ina) Stomachb) Duodenumc) Pancreasd)  Liver \nSelect and explain. \nA. ac, B. ab, C. ad, D. bc', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Motilin secreted by\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 M cells of duodenal mucosa (Main)\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Stomach\n\xa0\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Colon', 'role': 'assistant'}]