This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ocular motility and squint, Subject name: Ophthalmology
[{'content': 'Longest and thinnest extrocular muscle - \nSelect and explain. \nA. SR, B. IR, C. SO, D. IO', 'role': 'user'}, {'content': 'Answer: C \nExplanation: SO arises from the bone above and medial to the optic foramina. It runs forward and turns around a pulley- " the trochlea" and is inseed in the upper and outer pa of the sclera behind the equator. Ref;A.K.Khurana; 6th edition;Page no:336', 'role': 'assistant'}]