What does the myelin sheath do?

choices A and C
help electrical impulses travel through neurons
delay mental development as needed or is appropriate
cover the neurons with a fatty coating

Myelin is an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells.

answer; ///(a) and (c) newspaper article and instruction manual; //so the answer is (e)

is there a passage to this question if so plz take a picture