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: ENT
[{'content': 'In pure tone audiogram the symbol X is used to mark- \nSelect and explain. \nA. Air conduction in right ear, B. Air conduction in left ear, C. Bone conduction in right ear, D. No change in air conduction in right ear', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]