The Early Development of a Globular Colony (With Flagella Inward)that

The early development of a globular colony (with flagella inward) that then turns inside-out (with flagella outward) is

A) called an undulating membrane and is common among ciliates.
B) a pseudoplasmodium and only found in protozoans.
C) called inversion,and it is very common in early development in many animal groups.
D) called inversion,and it is very rare among animals,only occurring in colonial flagellates and sponges.
E) called reverse gastrulation and it is very rare among animals.