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': 'Density of cells in adult corneal endothelium ? \nSelect and explain. \nA. 2000 cells/mm2, B. 3000 cells/mm2, C. 4000 cells/mm2, D. 5000 cells/mm2', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., 3000 cells/mm2 The cell density of corneal endothelium is around 3000 cells/mm2 in young adults, which decreases with the advancing age.", 'role': 'assistant'}]