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': 'Main MOA brimonidine in glaucoma ? \nSelect and explain. \nA. Decreased aqueous secretion, B. Increased trabecular outflow, C. Increased uveoscleral outflow, D. Reduce vitreous volume', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Decreased aqueous secretion", 'role': 'assistant'}]