The correct option is D Aschelminthes
When a body cavity lined with mesoderm is present in between the gut and the body wall, it is known as a coelom. All the members of Annelida, Arthropoda, Mollusca, Echinodermata, Hemichordata and Chordata are coelomic animals.
The animals in which a body cavity is absent are called acoelomates. Example: Platyhelminthes.
In a few organisms, the body cavity is not lined by mesoderm. Instead, the mesoderm is distributed between the ectoderm and the endoderm. They are known as pseudocoelomates.