If a Drug Prevents Sodium from Crossing the Membrane of an Axon

If a drug prevents sodium from crossing the membrane of an axon, what changes in the activity of the neuron?

A) An increased number of potassium ions cross instead.
B) It increases its rate of consumption of glucose and other fuels.
C) It stops transmitting action potentials.
D) It transmits action potentials at a greater than usual velocity.