This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: A.N.S., Subject name: Pharmacology
[{'content': 'Non-selective beta blocker used in glaucoma: \nSelect and explain. \nA. Timolol, B. Metoprolol, C. Betaxolol, D. Propranolol', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. TimololTimolol, betaxolol and levobunolol are the beta blockers given in open angle glaucoma. They decrease the synthesis of aqueous humor and thus decreasing the intraocular pressure. Out of the three drugs, Timolol is non-selective beta blocker.', 'role': 'assistant'}]