This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Zollinger Ellision Syndrome, Subject name: Medicine
[{'content': 'Not a feature of ZES? \nSelect and explain. \nA. Diarrhea non-responsive to fasting, B. Epigastric pain, C. Large gastric ulcer, D. Secretin study is the investigation of choice', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Feature of ZES. Diarrhea non- responsive to fasting (secretory diarrhea) Epigastric pain 2nd pa of Duodenum, Multiple duodenum ulcer (Not present in stomach) Secretin study in the IOC - BAO/MAO = 0.6', 'role': 'assistant'}]