Which of the following is true about Petromyzon?

Petromyzon (lamprey) is included under class Cyclostomata of Agnatha. Adults of Petromyzon (lamprey) are marine but migrate for spawning to freshwater. After spawning, within a few days, they die. Their larvae, after metamorphosis, return to the ocean.

Median fins are present but paired fins are absent.

Mouth is circular and sucking but lacks jaws.