The efficiency of cells to exchange materials with their environment is proportional to the surface area-to-volume ratio of cells. Which cell would have the highest exchange rate of metabolites with its environment?

A.)An oocyte cell (sphere) with a radius of 50 µm.
B.)An immune cell (sphere) with a radius of 8 µm.
C.)A neuronal cell (solid rectangle) with the dimensions 1 µm x 1 µm x 120 µm.
D.)An epithelial cell (solid rectangle) with the dimensions 3 µm x 10 µm x 20 µm.