This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuroanatomy, Subject name: Anatomy
[{'content': 'Great vein of Galen is formed by \nSelect and explain. \nA. Two internal cerebral veins, B. Superficial middle cerebral vein & deep middle cerebral vein, C. Anterior cerebral vein & basal vein, D. Internal cerebral veins & straight sinus', 'role': 'user'}, {'content': "Answer: A \nExplanation: (A) Two internal cerebral veins # GALEN'S VEINS: The internal cerebral veins; the great vein of Galen is formed by their union.> Anterior cerebral vein also known as Galen's vein.> Great cerebral vein or Great vein of Galen is formed by union of two internal cerebral veins. It terminates in the straight sinus.", 'role': 'assistant'}]