Answer
B.
Work Step by Step
While surface area-to-volume ratios can change with cell size (C.), the rate of diffusion (B.), which limits critical function for life such as removal of waste and transport of nutrients around the cell, is most critical for limiting cell size. DNA varies widely in amount from cell to cell and, thus, is not relevant (D.). A. can be eliminated since the ability to produce proteins and organelles can increase rapidly with cell size.
