This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'Stem cells are taken from ? \nSelect and explain. \nA. Skin, B. Bone marrow, C. Oral mucosa, D. Elementary tract', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Stem cells are undifferentiated pluripotent cells. They are present in bone marrow of adults. Basic Pathology, Robbins. Page no.:60', 'role': 'assistant'}]