At rest, a neuron has a lower concentration of sodium than the surrounding fluid. The neuron also has a higher concentration of potassium inside the cell. The sodium-potassium ion pump is used to maintain the neuron in the resting state. Which of the following statements is true?
a. Remaining at rest requires the use of ATP.
b. Remaining at rest requires an input of sodium.
c. Remaining at rest requires the activation of cotransporters.
d. Remaining at rest requires decreased permeability of the membrane.