Na⁺ Ion Concentrations Are Higher Outside the Cell Than Inside

Na⁺ ion concentrations are higher outside the cell than inside the cell.What type of transport system is required to move Na⁺ ions in and out of the cell?

A) Na⁺ moves into the cell by facilitated diffusion and out of the cell by active transport
B) Na⁺ moves in and out of the cell by passive diffusion
C) Na⁺ moves in and out of the cell by active transport
D) Na⁺ moves into the cell by active transport and out of the cell by facilitated diffusion
E) Na⁺ moves into the cell by facilitated diffusion and can not move out of the cell