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: Pharmacology
[{'content': 'Which of the following drugs is not used topically for treatment of open angle glaucoma? \nSelect and explain. \nA. Lanatoprost, B. Brimonidine, C. Acetazolamide, D. Dorazolamide', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Acetazolamide", 'role': 'assistant'}]