The functional junction between two neurons is called as

The correct option is A Synapse
The synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another cell. Synapses are essential to neuronal function: neurons are cells that are specialized to pass signals to individual target cells and synapses are the means by which they do so. At a synapse, the plasma membrane of the signal-passing neuron (the presynaptic neuron) comes into close apposition with the membrane of the target (postsynaptic) cell. Both the presynaptic and postsynaptic sites contain extensive arrays of molecular machinery that link the two membranes together and carry out the signaling process. In many synapses, the presynaptic part is located on an axon, but some postsynaptic sites are located on a dendrite or soma.

Therefore, the correct answer is option A.