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: Physiology
Which of the following are unmyelinated nerve fibers? 
Select and explain. 
A. Proprioceptive fibers, B. Motor neuron to muscle, C. Postganglionic sympathetic fibers, D. Motor nerve to intrafusal fibers
C: Postganglionic sympathetic fibers
Answer: C: Postganglionic sympathetic fibers 
Explanation: Ans. is 'c' i.e., Postganglionic sympathetic fibers[Ref Ganong 24h/e p. 92; Principles of medical physiology p. 5I2lType C fibers are unmyelinated fibers which include postganglionic autonomic fibers,