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
[{'content': 'True about Optic disc – a) Horizontal diameter 1.76 minb) Vertical diameter 1.88 mmc) Contain 1 million nerve fibred) Central retinal artery directly supplies this area \nSelect and explain. \nA. ab, B. bc, C. abc, D. bcd', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]