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': 'Marcus Gunn pupil along with proptosis indicates: \nSelect and explain. \nA. Involvement of ciliary ganglion, B. Compression of optic nerve, C. Compression of inferior division of 3rd nerve, D. Compression of sympathetic nerves of the eyeball', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Compression of optic nerve', 'role': 'assistant'}]