Which Statement Best Describes Rapid Depolarization

Which statement best describes rapid depolarization?

A) The membrane rapidly depolarizes at the site of stimulation causing a firing threshold that is followed by displacement of the calcium ions.
B) The membrane rapidly depolarizes once the firing threshold has been achieved allowing a flood of sodium ions into the axoplasm.
C) The membrane rapidly depolarizes along the entire nerve until the strength of the stimulus increases enough to cause an impulse.
D) The membrane rapidly depolarizes following the refractory resting state.