Megalecithal eggs also known as polylecithal or macrolecithal eggs are those eggs where enormous amount of yolk is present in egg and here yolk is several times greater than cytoplasm. It is characteristic of birds. In discoidal meroblastic cleavage, the cleavage furrows do not penetrate the yolk. The embryo forms a disc of cells, called a blastodisc, on top of the yolk. It is characteristic of birds. Hence, option D is correct.