Which of the following is false regarding the membrane potential? a) the resting membrane potential is maintained by solely by passive transport processes. b) in their resting state, all body cells exhibit a resting membrane potential. c) the resting membrane potential is determined mainly by the concentration gradients and differential permeability of the plasma membrane to k+ and na+ions. d) the resting membrane potential occurs due to active transport of ions across the membrane due to the sodium-potassium pump.