What Causes the Rapid Change in the Resting Membrane Potential

Multiple Choice

What causes the rapid change in the resting membrane potential that initiates an action potential?

A) Potassium gates open and potassium rushes into the cell changing the membrane potential from negative to positive.
B) Sodium gates open and sodium rushes into the cell changing the membrane potential from negative to positive.
C) Sodium gates close allowing potassium into the cell to changing the membrane potential from positive to negative.
D) Potassium gates close allowing sodium into the cell to change the membrane potential from positive to negative.