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': "Which is not affected in lesion of posterior column of spinal cord ? \nSelect and explain. \nA. Romberg's sign, B. Temperature sense, C. Vibration sense, D. Ataxia", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]