Which of These Statements Applies to Membrane Potential

Which of these statements applies to membrane potential

A) It refers to a separation of charges across the membrane, or to a difference in the relative numbers of + and - charges in the ECF and the ICF.
B) It is measured in units of millivolts, with the sign always designating the charge on the outside.
C) It is less at the equilibrium potential for K⁺ than at resting membrane potential.
D) It refers to the presence of K⁺ inside the cell.