This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Brain , Subject name: Anatomy
[{'content': 'Oligodendrocytes are impoant in \nSelect and explain. \nA. Myelin formation, B. Blood brain barrier, C. Phagocytosis, D. Collagen synthesis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Oligodendrocytes:According to their distribution they may be of intrafscicular,or perineural. The intrafascicular cells are found in the myelinated tracts.The perineuronal cells are seen on the surface of the somata of the neurons. REF.BDC Handbook of general anatomy,4th edition', 'role': 'assistant'}]