This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
[{'content': "Which of the following sites is responsible for the amnestic defect in Wernicke's Korsakoff -syndrome \nSelect and explain. \nA. Mamillary body, B. Thalamus, C. Subthalmic nucleus, D. Medical fore brain bundle", 'role': 'user'}, {'content': "Answer: B \nExplanation: Harrison's principles of internal medicine 17th edition. *The amnestic defect is related to lesions of dorsal medial nuclei of thalamus", 'role': 'assistant'}]