The correct option is C Synapse
Neuron is the structural and functional unit of nervous system. It consists of dendrites, axon and soma. Dendrites are the small extension of nerve cells that receives signals from sensory receptors or other neurons.
The long extension of cell body of nerve cell is called as axon that serves to conduct the nerve impulse away from the cell body.
Two neurons are never physically connected to each other and synapse place where two neurons are in close connection to facilitate transmission of information from one neuron to the next one.
The extracellular space between two neurons is known as synaptic cleft. Nerve impulse is all or none response of nerve fibres and is defined as wave of change in polarity of neuron membrane, caused by movement of ions across the membrane.
So, the correct answer is option B.