Anatomy The optic nerve is a tract of the diencephalon that is not completely myelinated until A 5 years after bih B 2 years after bih C 1 year after bih D 3 months after bih 💡 Explanation The optic nerve is a tract of the diencephalon that is not completely myelinated until ✓ Correct Answer: D. 3 months after bih