Because of the Voltage Difference Across the Membrane of a Neuron

Because of the voltage difference across the membrane of a neuron and the different ion concentrations on either side of the membrane, ions would cross the membrane if they could.What is the importance, therefore, of a neuron maintaining a membrane potential?

A) It maintains an electrical balance in the cell.
B) Cellular activity requires more Na⁺ than K⁺.
C) If the ions were in equilibrium, the cell would shrink by losing water through osmosis.
D) It prevents the electrical and chemical gradients from reaching equilibrium, a process that would require a great deal of energy.
E) It allows a cell to respond to a stimulus that changes its permeability to ions.