In a Voltage Clamp Experiment, You Observe That the Magnitude

In a voltage clamp experiment, you observe that the magnitude of the sodium current increases when the membrane potential is stepped between -45 and +10 mV. Why?

A) The driving force on sodium increases as membrane potential increases.
B) The equilibrium potential for sodium increases as membrane potential increases.
C) More sodium channels open as membrane potential increases.
D) The resting potential of the neuron increases as membrane potential increases.
E) The leak conductance increases as membrane potential increases.