This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Primary Angle-Closure Glaucoma, Subject name: Ophthalmology
What is the drug of choice for treating angle closure glaucoma? 
Select and explain. 
A. Pilocarpine, B. Timolol, C. Dipiveffine, D. Apraclonidine
A: Pilocarpine
Answer: A: Pilocarpine 
Explanation: Ans. is 'a' i.e., Pilocarpine o Has been explained in previous sessions.