At rest, why is the transmembrane potential of a neuron (-70 mV) closer to the potassium equilibrium potential (-90 mV) than it is to the sodium equilibrium potential (+66 mV)?
A) More potassium channels are open.
B) Sodium-potassium pumps are more active.
C) There are more sodium ions inside the cell.
D) Potassium ions are less permeable than sodium ions.