This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ocular Embryology& Anatomy, Subject name: Ophthalmology
[{'content': 'The Arrow points towards \nSelect and explain. \nA. Superior Rectus, B. Trochlea, C. Inferior Rectus, D. Annulus of Zinn', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The structure marked is the trochlea and the muscle is superior oblique', 'role': 'assistant'}]