This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diseases of orbit, Lids and lacrimal apparatus, Subject name: Ophthalmology
[{'content': 'Volume of orbit is- \nSelect and explain. \nA. 19ml, B. 29ml, C. 39ml, D. 49ml', 'role': 'user'}, {'content': 'Answer: B \nExplanation: *Volume of orbit is 29ml. Ref:AK Khurana Anatomy and Physiology of eye 7th/e p.418', 'role': 'assistant'}]