This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Brainstem, cerebellum and ventricles, Subject name: Anatomy
[{'content': "Which cranial nerve's fibers are myelinated by oligodendrocytes? \nSelect and explain. \nA. I, B. II, C. III, D. VII", 'role': 'user'}, {'content': 'Answer: B \nExplanation: The fibers of the optic nerve (CN II) are myelinated by oligodendrocytes. This is an impoant distinction from the Other cranial nerves ( myelinated by Schwann cells) because the optic nerve is considered a tract of the central nervous system', 'role': 'assistant'}]