Which of the following statements aptly describes the phylum "Annelida"?

• A. A group of animals in which the space between the ectoderm and endoderm is simply filled with mesenchymal mesodermal cells.
• B. A group of animals with long, flat body without true segmentation, that lives in water or moist soil or are parasitic invertebrates.
• C. A group of animals that have an elongated, cylindrical and unsegmented body.
• D. A group of animals that have an elongated body that is composed of partitions called metameres or annulations.