This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal System, Subject name: Physiology
[{'content': 'Enterochromaffin Cells in GIT secrete \nSelect and explain. \nA. Serotonin, B. Histamine, C. Both, D. None', 'role': 'user'}, {'content': 'Answer: C \nExplanation: More than 15 types of hormone-secreting enteroendocrine cells have been identified in the mucosa of the stomach, small intestine, and colon. Many of these secrete only one hormone and are identified by letters (G cells, S cells, etc). Others manufacture Serotonin or Histamine and are called enterochromaffin or ECL cells.', 'role': 'assistant'}]