This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pancreas, Subject name: Surgery
[{'content': 'The commonest pancreatic tumor is: \nSelect and explain. \nA. Ductal adenocarcinoma, B. Cystadenoma, C. Insulinoma, D. Non islet cell tumor', 'role': 'user'}, {'content': 'Answer: A \nExplanation: M/C type - Adenocarcinoma Non-specific Tumour Marker - CEA Specific Tumour Marker - CA 19.9 Chemotherapy Regimen - Gemcitabine MC site of metastasis - Liver M/C site for CA pancreas - Head > Body > Tail Neuroendocrine Tumors (NET) of Pancreas- M/C NET of Pancreases - Non-Functional (PPOMA)- M/C functional NET of Pancreas - Insulinoma- M/C functional & Malignant NET of Pancreas - Gastrinoma', 'role': 'assistant'}]