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
Group B fibers are present in: 
Select and explain. 
A. Intrafusal fibers of the muscle spindle, B. Golgi tendon apparatus, C. Autonomic preganglionic fibers, D. Spinothalamic tracts
C: Autonomic preganglionic fibers
Answer: C: Autonomic preganglionic fibers 
Explanation: None