Which of the following statements is most correct regarding the sodium-potassium pump?

A) The ATP driven pump operates as a symport system.
B) The pump transports 3 potassium ions into the cell for every 2 sodium ions it transports out of the cell.
C) Phosphorylation of the ATPase transport protein causes a conformational change resulting in the expulsion of sodium into the extracellular fluid.
D) When potassium binds to the ATPase transport protein, the protein is phosphorylated.
E) It is a secondary transport pump.