The Fact That a Neuron Fires in an All or Nothing

The fact that a neuron fires in an all or nothing manner means that

A) either all neurons in a particular brain area generate action potentials or none of them do.
B) a neuron either fires a full action potential or fires none at all.
C) neurons release all of their neurotransmitters with every firing, or they release none.
D) all dendritic receptor sites are bounded by neurotransmitters, or none of them are.