This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous system, Subject name: Physiology
The total volume of CSF is 
Select and explain. 
A. 50 ml, B. 100 ml, C. 150 ml, D. 275 ml
C: 150 ml
Answer: C: 150 ml 
Explanation: In humans, the volume of CSF is about 150 mL and the rate of CSF production is about 550 mL/d. Thus the CSF turns over about 3.7 times a day.(Ref: Ganong's Review of Medical Physiology Twenty-Third Edition)