Increasing Axon Diameter Decreases Membrane and Intracellular Resistance,so It Seems

Multiple Choice

Increasing axon diameter decreases membrane and intracellular resistance,so it seems the two might cancel each other out in terms of their effect on the conduction speed.Yet,conduction speed is increased by increasing diameter size.Why?

A) Membrane resistance doesn't really affect conduction speed that much.
B) Intracellular resistance doesn't really affect conduction speed that much.
C) Membrane resistance decreases linearly while intracellular resistance decreases by the square of the radius.
D) Intracellular resistance decreases linearly while membrane resistance decreases by the square of the radius.