Which of the following has non-myelinated nerve fiber?
The correct option is B Autonomic nerves
Myelin sheath is a fatty acid containing a white creamy layer that forms cover the axons of myelinated fibres. These nerve fibres carry out fast and saltatory conduction of nerve impulse and are found in cranial and spinal nerves. The optic nerve is a cranial nerve. Autonomic nerves are non-myelinated fibres that lack myelin sheath and carry out slow but smooth conduction of nerve impulse. Thus, the correct answer is option D.