This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'Hemiballismus is due to lesion o \nSelect and explain. \nA. Caudate nucleus, B. Subthalamic nucleus, C. Putamen, D. None', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Hemiballismus is lesion of subthalamic nucleus', 'role': 'assistant'}]