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': 'Treatment of primary open angle glaucoma: \nSelect and explain. \nA. Timolol maleate, B. Atropine, C. Acetazolamide, D. Prostaglandin analogue', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Timolol maleate', 'role': 'assistant'}]