Which of the following statements about the sodium-potassium pump is correct? a. The sodium-potassium pump requires ATP to pump sodium and potassium ions from higher to lower concentrations along their concentration gradients. b. The sodium-potassium pump brings sodium into a neuron during depolarization and forces potassium out of a neuron during depolarization c. The activity of the sodium-potassium pump is needed after every action potential to restore resting potential. d. The sodium-potassium pump is a leak channel that allows passive movement of sodium and potassium ions down the concentration gradient.