Refer to the Figure Below Showing Concentrations of Three Ions

Multiple Choice

Refer to the figure below showing concentrations of three ions inside and outside a cell, as well as the direction of transport of each ion facilitated by a membrane protein. Which ions are moved by active transport and why?

A) K⁺ and Na⁺, because they are present in millimolar concentrations in the cell
B) Ca²⁺, because it is present in concentrations below the micromolar level in the cell
C) K⁺, because it is being moved into the cell and not out of the cell
D) K⁺, Na⁺, and Ca²⁺, because they are charged particles
E) K⁺, Na⁺, and Ca²⁺, because they are moving from lower to higher concentration