The answer is; A
Neurons are connected to each other with synaptic junctions. When a presynaptic neuron receives an impulse and this impulse reaches the end of the axon, it induces the release of chemical neurotransmitters into the synaptic cleft. The neurotransmitters diffuse (in milliseconds) and bind to the receptors in the synaptic cleft (in the postsynaptic neuron) and this induces an impulse in the postsynaptic neuron. This is how the impulse is relayed from neuron to neuron.
