Final answer:
The axon is the part of the neuron that transmits an electrical signal to a target cell, supported by satellite cells such as Schwann cells that form the myelin sheath.
Step-by-step explanation:
Neurons are specialized cells within the nervous system that transmit information to other nerve cells, muscle, or gland cells. The specific part of the neuron that transmits an electrical signal to a target cell is the axon. Neurons consist of a cell body (soma), which contains the nucleus and most of the cytoplasmic organelles; dendrites, which are tree-like structures that receive messages from other neurons; and a single axon, which is a long, slender projection that conducts electrical impulses away from the neuron's cell body.
Within the neuron, it is the axon that is supported by satellite cells, known as glial cells. These cells, such as Schwann cells in the peripheral nervous system, form the myelin sheath around the axon, which increases the speed of electrical signal conduction. As such, the answer to the given question is 'd. axon', which carries the action potential away from the neuron's cell body to another excitable cell.