Which Statement(s) Is/are True About Membrane Potentials

Multiple Choice

Which statement(s) is/are true about membrane potentials?

A) They are differences in electrical charge on opposite sides of a membrane
B) They are measured in millivolts, with the sign designating the charge on the outside
C) They exist because the ECF as a whole is positively-charged and the cytosol as a whole is negatively charged
D) They are always positive during the resting state
E) All of the above statements are true.