Final answer:
The repair of damaged neurons is assisted by neurotrophic factors secreted by Schwann cells, which produce myelin sheaths for axons in the peripheral nervous system.
Step-by-step explanation:
Repair of damaged neurons can be assisted by certain neurotrophic factors secreted by the Schwann cells or oligodendrocytes. Schwann cells produce the myelin sheaths that surround many axons in the peripheral nervous system, and oligodendrocytes serve a similar function in the central nervous system. Myelin is a lipid that provides an insulating layer to axons, allowing electrical signals to be transmitted more efficiently along the nerve cell.
Correct response to the question posed is D) Schwann cells. These cells support neuron function by creating an environment conducive to neural repair, such as myelination which enhances electrical impulse transmission. Whereas the cell body (or soma) and dendrites are involved in processing signals within the neuron itself, and the axon is responsible for transmitting the signal to the target, it is the Schwann cells that are instrumental in the repair and maintenance of the neurons by producing myelin.