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: Surgery
[{'content': 'Site of transplantation in Islet cell transplant for diabetes mellitus \nSelect and explain. \nA. Forearm muscles, B. Pelvis, C. Thigh, D. Injected into the portal vein', 'role': 'user'}, {'content': 'Answer: D \nExplanation: • The islets are then purified from the dispersed tissue by density-gradient centrifugation and can be delivered into the recipient liver (the preferred site for transplantation) by injection into the portal vein.', 'role': 'assistant'}]