What Keeps an Action Potential Continuing Down an Axon

Multiple Choice

What keeps an action potential continuing down an axon?

A) At each successive segment of the axon, the action potential is regenerated by depolarization and the movement of ions across the axon's membrane.
B) Neurotransmitters are constantly being released to generate the action potential at each successive segment of the axon.
C) Action potentials are conducted down the axon, just as electricity is conducted through a wire.
D) Ion channels open and close at the nodes of Ranvier, allowing neurotransmitters to enter into the axon and regenerate an action potential at each node.