Which one of the following is NOT a characteristic of phylum Annelida?

Annelids are triploblastic, bilaterally symmetrical animals with the organ-system level of organisation.
They are true coelomates: the body cavity is a true coelom lined by mesoderm on both sides.
A pseudocoelom, in which the body cavity is not lined by mesoderm, is characteristic of Aschelminthes (roundworms), not Annelida.
Their body is metamerically segmented, which gives the phylum its name (annulus = little ring).
They have a closed circulatory system, and the nervous system consists of paired ganglia connected by lateral nerves to a double ventral nerve cord.
So segmentation, a ventral nerve cord and a closed circulatory system are characters of Annelida, but a pseudocoelom is not.