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
[{'content': 'Metabolically active layer of cornea is: \nSelect and explain. \nA. Endothelium, B. Stroma, C. Descernets membrane, D. Epithelium', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Endothelium', 'role': 'assistant'}]