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: Medicine
[{'content': 'Best provocative test for diagnosis of Gastrinoma is: \nSelect and explain. \nA. Ca++ infusion test, B. Secretin injection test, C. ACTH stimulation test, D. Steroid assay', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Secretin injection test) Gastrinomas (Zollinger Ellison Syndrome) are characterized by peptic ulceration due to hypersecretion of gastrin by a non-beta cell tumor. Secretin injection test is the most valuable provocative test in identifying patients with ZES.', 'role': 'assistant'}]