A cell’s rate of exchanging materials with the environment positively relates to its surface area-to-volume (SA/V) ratio. Cell shape also correlates to its function. Also, spherical cells have the smallest surface area compared to all cells of the same volume but different shapes. Which of the following cell types is likely to have the highest rate of material change?

a flat epithelial cell with a diameter of 5 micron
a spherical immune cell with a diameter of 5 micron
a round mammalian oocyte with a diameter of 1 millimeter
a near-spherical intestinal stem cell with a diameter of 8 micron