This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Ophthalmology
[{'content': 'Longest pa of the optic nerve is \nSelect and explain. \nA. Intraocular, B. Intracranial, C. Intraorbital, D. Intracanalicular', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The optic nerve is about 47- 50 mm in length and can be divided into 4 pas : intraocular (1mm), intraorbital (30mm), intracanalicular (6-9mm) and intracranial (10mm). Refer comprehensive ophthalmology 6th edition , A K Khurana , page no. 310.', 'role': 'assistant'}]