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': 'Selective alpha 2 agoinst used in glaucoma ? \nSelect and explain. \nA. Tirriolol, B. Epinephrine, C. Dipivefrine, D. Brimonidine', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Brimonidine", 'role': 'assistant'}]