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
Alpha 2 agonist used in glaucoma is ? 
Select and explain. 
A. Brimonidine, B. Timolol, C. Phenylephrine, D. Reserpine
A: Brimonidine
Answer: A: Brimonidine 
Explanation: Ans. is 'a' i.e., Brimonidine