This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lens, Subject name: Ophthalmology
[{'content': 'Epithelium is absent in lens on - \nSelect and explain. \nA. Anterior surface, B. Anterior pole, C. Posterior surface, D. At zonular attachment', 'role': 'user'}, {'content': 'Answer: C \nExplanation: There is no posterior epithelium, as these cells are used up in filling the central cavity of lens vesicle during development of the lens.', 'role': 'assistant'}]