This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous Nervous System, Subject name: Physiology
[{'content': 'The total volume of CSF in an adult is about - \nSelect and explain. \nA. 100-150 ml, B. 300-350 ml, C. 500-550 ml, D. 600-650 ml', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 100-150 ml o The major source of CSF is the choroidal plexus of all 4 ventricles, mainly in two lateral ventricles, o Other sources of CSF are ependymal cells of the ventricles and the brain itself, via perivascular spaces, o The total volume of CSF in an adult is about 125-150 ml. o The rate of formation of CSF is about 500-550 ml/day. Thus the CSF is replaced 3-4 times every day.", 'role': 'assistant'}]