Which one of the following pairs of animals comprises 'jawless fishes'?

Petromyzon belongs to which of the following groups?

Identify the correct option for $Cyclostomata$ $:-$

Which of the following statements are correct for Cyclostomata?
$I$ - They have a sucking and circular mouth without jaws.
$II$ - Their body is devoid of scales and paired fins.
$III$ - Their cranium and vertebral column are cartilaginous.
$IV$ - They have a closed type of circulatory system.
$V$ - Cyclostomes live in freshwater,but migrate to the ocean for spawning.
$VI$ - They show direct development.

Match the name of the animal (Column-$I$) with one characteristic (Column-$II$), and the phylum/class (Column-$III$) to which it belongs.

Animals of this class are marine,but migrate to freshwater for spawning.