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': 'Which is the best investigation for metastatic gastrinoma? \nSelect and explain. \nA. Selective aerial secretin injection, B. Octreoscan, C. BAO/MAO ratio, D. Ultrasound', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In case of gastrinoma showing metastasis the diagnostic sensitivity of octreoscan is 80-100%. In contrast in primary gastrinoma, Endoscopic ultrasound shows a sensitivity of 80-100% versus octreoscan which shows a sensitivity of 67-86%.', 'role': 'assistant'}]