To which phylum does the 'Nereis' (Sandworm) belong?

True coelom or body cavity occurs in

Which of the following species are earthworms?
$I-$ Nereis,$II-$ Pheretima
$III-$ Hirudinaria,$IV-$ Lumbricus
$V-$ Periplaneta

In which of the following is the segmentation best represented?

Given below are two statements. One is labelled as Assertion $(A)$ and other is labelled as its Reason $(R)$.
Assertion $(A) :$ In $Nereis$,longitudinal and circular muscles help in locomotion.
Reason $(R) :$ $Nereis$ is an aquatic annelid which is monoecious and possesses lateral appendages called parapodia,which help in swimming.

Animals having multiple or numerous setae are included under