The correct option is B Petromyzon
Petromyzon is a cyclostome. Cyclostomes are marine but migrate to freshwater for spawning. The process of release of eggs into the water by aquatic animals is called spawning. The larva undergoes metamorphosis in freshwater and then moves into the ocean.
Eels look like a snake but are fish and it lives in both saline and freshwater habitats. The eels have small, but strong jaws with numerous small teeth.
The Exocoetus is a marine fish with a wide jaw bearing teeth. Its body is covered with cycloid scales and the pectoral fin is modified for gliding.
Clarias resemble eels in having a slender body. They have long dorsal and anal fins. Their mouths have four pairs of barbels (whisker like sensory organ) near their mouth.