Which of the Following Statements About the Refractory Period of a Membrane

Which of the following statements about the refractory period of a membrane is true?

A) The absolute refractory period refers to the period of time during which another action potential cannot be initiated in that part of the membrane that has just undergone an action potential, no matter how great the strength of the stimulus
B) The relative refractory period refers to the period of time during which another action potential can be initiated in that part of the membrane that has just undergone an action potential, if the stimulus is strong enough
C) The refractory period prevents the action potential from spreading back over the part of the membrane that just underwent an action potential
D) The refractory period places an upper limit on the frequency with which a nerve cell can conduct action potentials
E) All of the choices are correct