Which of the Following Describes a Function of Cerebrospinal Fluid

Multiple Choice

Which of the following describes a function of cerebrospinal fluid?
1) Maintain optimum ionic environment
2) Maintain pH homeostasis
3) Provide circulation for exchange of nutrients/wastes
4) Serve as a shock absorbing fluid system of spinal cord
5) Provide buoyancy of the brain

A) 1,2,3
B) 1,4,5
C) 1,3,5
D) 2,3,4,5
E) 1,2,3,4,5