Immediately after an action potential passes along an axon, it is ...

[geoffrey]

Immediately after an action potential passes along an axon, it is not possible to generate a second action potential; thus, we state that the membrane is briefly
A) hyperexcitable.
B) refractory.
C) fully depolarized.
D) above threshold.
E) at the equilibrium potential.

[j_sun]

I recall doing this last year, it's B, bye bye!