Which type of metamerism is observed in earthworms?

Read the following four statements $(A-D)$:
$(A)$ Annelids possess only longitudinal muscles which help in locomotion.
$(B)$ Nephridia do not help in excretion and osmoregulation.
$(C)$ Closed type circulatory system is present in most of annelids.
$(D)$ Members of phylum Annelida are triploblastic,metamerically segmented,and acoelomate.
How many of the above statements are incorrect?

True coelom or body cavity occurs in

The term $Annulus$ is derived from which language?

Which one of the following exhibits a concentric "tube within a tube" body plan?

Closed circulatory system is found in?