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': 'Food in stomach \nSelect and explain. \nA. Enterochromaffin cells, B. Adrenal medulla, C. Adrenal coex, D. Thyroid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Enterochromaffin cells', 'role': 'assistant'}]