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: Ophthalmology
All of the following are pas of optic nerve except 
Select and explain. 
A. Intraorbital Pa, B. Intracanlicular Pa, C. Cisternal Segment, D. Intra cavernal Pa
D: Intra cavernal Pa
Answer: D: Intra cavernal Pa 
Explanation: Answer- D. Intra cavernal PaOptic nerve is about 47-50 mm in length and can be divided into 4 pas :Intraocular pa (l mm)Intraorbital pa (30 mm)Intracanalicular pa (6-9 mm)Intracranial pa (10 mm)