50. During the rapid increase in membrane potential seen in the upsweep of the action potential, whichdescription of the following is most correct?
(A)The sodium/potassium pump has reversed directions and is pumping sodium in and potassium out.
(B) Both the activation and inactivation gates of the voltage-gated sodium channels are open.
(C) The potassium leak channels are closed.
(D)The sodium leak channels are closed.
(E)The voltage-gated potassium channel is open.