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': "Brown's syndrome involves \nSelect and explain. \nA. Superior rectus, B. Superior oblique, C. Medial rectus, D. Lateral rectus", 'role': 'user'}, {'content': "Answer: B \nExplanation: Brown's syndrome is due to fibrous tightening of the superior oblique tendon.", 'role': 'assistant'}]