This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Brain , Subject name: Anatomy
[{'content': 'Pa of neural tube from which corpus callosum develops \nSelect and explain. \nA. Lamina terminalis, B. Basal lamina, C. Alar lamina, D. Roof plate', 'role': 'user'}, {'content': "Answer: A \nExplanation: Initially, corpus callosum forms a small bundle in the lamina terminalis and later extends first anteriorly and then posteriorly, arching over the thin roof of the diencephalon. It connects the nonolfactory areas of the right and the left cerebral coices. Ref: Gray's39e/p-518", 'role': 'assistant'}]