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': 'β-blockers act in glaucoma by - \nSelect and explain. \nA. Increased aqueous outflow, B. Decreased aqueous production, C. Reduce vitreous volume, D. None', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]