Final answer:
The correct statement is that a larger diameter of an axon leads to a faster rate of transmission due to less resistance. This is enhanced by the presence of myelin, which allows for faster saltatory conduction as compared to continuous conduction in unmyelinated axons.
Step-by-step explanation:
The larger the diameter of the axon, the faster the rate of transmission. This is because axons with greater diameters offer less resistance to the flow of ions that carry the electrical signal, allowing the action potential to propagate more swiftly. This concept is analogous to how water flows more rapidly in a wide river than in a narrow creek.
This principle applies similarly to electrical circuits, where a wider wire reduces resistance and allows for quicker transmission of electrical current. In contrast, a smaller axon diameter increases resistance and slows down the transmission of the action potential, just as a thinner wire would slow the transmission of electricity. The presence of myelin also speeds up conduction by insulating the axon and facilitating saltatory conduction, where the electrical signal 'jumps' from node to node, which is far faster than the continuous conduction in unmyelinated axons.