The correct option is D Abyssal region- light compensation
The deepest part of the ocean is called as the abyssal zone. It is host to many species of invertebrates and fish including such oddities as the coelacanth, a prehistoric fish once thought extinct and found in the depths of the Indian ocean and other fish that glow in the dark via a process called as photoluminescence. The abyssal zone is very cold, and highly pressurized.