This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
[{'content': 'CSF is similar to \nSelect and explain. \nA. Endolymph, B. Perilymph, C. Coilymph, D. Urine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Perilymph resembles extracellular fluid and rich in Na ions. It communicates with CSF through aqueduct of the cochlea which opens into scala tympani near the round window. Reference: Dhingra 6th edition.', 'role': 'assistant'}]