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
Which antiglaucoma drug decreases aqueous formation ? 
Select and explain. 
A. Prostaglandins, B. Beta - blockers, C. Mannitol, D. Pilocarpine
B: Beta - blockers
Answer: B: Beta - blockers 
Explanation: Ans. is 'b' i.e., Beta - blockers