This Graph Shows the Rate of Cell Division in a Developing

This graph shows the rate of cell division in a developing frog embryo.
Why does the rate of growth decrease dramatically after the point indicated by the arrow?

A) At this point, development switches from rapid cell growth to cell differentiation and migration.
B) This arrow indicates when the embryo begins to run out of its internal food source and must find another source to continue developing.
C) This is when fertilization occurs. Before this point, the single-celled egg was growing quickly as it stored food. After this point, growth slows for the more deliberate process of development.
D) At the time indicated by the arrow, the trophoblast separates from the inner cell mass and the two tissues begin to divide at different and slower rates.