The embryo doesn't grow larger during the stage known as cleavage. What is going on in the embryo ...

The embryo doesn't grow larger during the stage known as cleavage. What is going on in the embryo during this process?
A) Cleavage is just the stage at which cells begin to differentiate; that is, endodermal cells start to look different from ectodermal and mesodermal cells.
B) The cells are dividing at this stage, but all the cytoplasm is being split between resulting cells without the formation of new cytoplasm.
C) Cleavage is the formation of the gastropore that is used to differentiate protostomes and deuterostomes.
D) Cleavage is the process by which the polarity of the cell is established; that is, the anterior is distinguished from the posterior.