We have to consider that when a cell is smaller with respect to another higher cell, there is better efficiency in the metabolic processes they carry out since a smaller cytoplasm and a smaller cell membrane surface can represent a faster movement of molecules inside the cell, from the inside to the outside, and vice versa. Having this clear, we can say that a reason why a cell would divide when it reaches its growth limit is that smaller cells can more easily transport nutrients and remove wastes, as stated in the B answer option. This is because small cells have a major surface volume ratio than more big cells, which allows them to, in a more reduced space, move molecules more with greater ability.
An example of this can be seen in the following picture, which represents three different cells of different sizes, having the smaller cells at the left of the image, a higher surface volume ratio (sa:v), and at the right part of the image, a bigger cell with a lower surface volume ratio.
SA= surface area
V= volume
SA:V= surface area volume ratio, or surface volume ratio.