The sodium-potassium ion pump will __________.

• A. pump three potassium ions out of the cell for every two sodium ions it brings into the cell
• B. pump one potassium ion out of the cell for every ion of sodium it brings into the cell
• C. pump one sodium ion out of the cell for every ion of potassium it brings into the cell
• D. pump three sodium ions out of the cell for every two ions of potassium it brings into the cell