This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Ophthalmology
which layer of cornea helps in maintaining hydration OF stroma of cornea 
Select and explain. 
A. Descement membrane, B. Endothelium, C. Epithelium, D. stroma
B: Endothelium
Answer: B: Endothelium 
Explanation: REF : AK KHURANA 7TH ED