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: Unknown
[{'content': 'Site for placing an electrode in auditory brain stem Implant is: \nSelect and explain. \nA. Sinus tympani, B. Recess of fourth ventricle, C. Round window, D. Lateral ventricle', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ref. Diseases of Ear, Nose and Throat. Pg 127\n\xa0\nAuditory brainstem implants have three main parts:\n\nA microphone and sound processor positioned behind the ear to pick up sounds\nA decoding chip placed under the skin to transmit information picked up by the microphone\nElectrodes connected directly to the brainstem(4th ventricle recess), when stimulated, alert you to sound', 'role': 'assistant'}]