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
The most important action of beta-blockers in glaucoma is which of the following: 
Select and explain. 
A. Membrane stabilizing effect, B. Retinal neuron protecting effect, C. Decrease in the production of aqueous humor, D. Pupillary constriction
C: Decrease in the production of aqueous humor
Answer: C: Decrease in the production of aqueous humor 
Explanation: None