This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Eye, Nose and Ear, Subject name: Anatomy
[{'content': 'The optic cup is an evagination of which of the following? \nSelect and explain. \nA. Telencephalon, B. Diencephalon, C. Mesencephalon, D. Metencephalon', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The optic cup and its derivatives--the retina and optic nerve--develop from the diencephalon.', 'role': 'assistant'}]