Why Are Action Potentials Sometimes Described as Being "All-Or-None" in Character

Multiple Choice

Why are action potentials sometimes described as being "all-or-none" in character?

A) The rate of propagation of an action potential down an axon is independent of stimulus strength.
B) They are associated with an absolute refractory period.
C) A supra-threshold stimulus is required to stimulate an action potential during the relative refractory period.
D) An action potential occurs whenever a suprathreshold stimulus occurs,and its amplitude does not vary with the size of a stimulus.
E) Action potentials are always the same size,even when ion gradients vary in size.