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': 'The pancreas arises from which embryonic germ layer \nSelect and explain. \nA. Ectoderm, B. Endoderm, C. Mesoderm, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]