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': 'Oldest cells of Lens are in \nSelect and explain. \nA. Nucleo - cortical junction, B. Nucleus, C. Anterior surface of lens, D. Posterior surface of lens', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Lens contains oldest cells in its Nucleus.', 'role': 'assistant'}]