This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Introduction to Central Nervous System, Subject name: Physiology
[{'content': 'Slow conduction velocity is seen with which of the following nerve fibers? \nSelect and explain. \nA. Preganglionic autonomic nerve fibers, B. Postganglionic autonomic nerve fibers, C. Motor nerves, D. Sympathetic nerve fibers', 'role': 'user'}, {'content': "Answer: B \nExplanation: Slow conduction velocity is seen in 'C'- fibers because they are unmyelinated. These are post ganglionic sympathetic nerve fibers.", 'role': 'assistant'}]