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 cochlear implants electrodes are most commonly placed at - \nSelect and explain. \nA. Oval window, B. Round window, C. Horizontal semicircular canal, D. Cochlea', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]