Answer :
The right option is; B. It could scrape food off the ocean floor.
This adaptation could have helped the fish to scrape food off the ocean floor.
The abyssopelagic zone is the part of the ocean that extends from waters directly above the continental rise down to about 6000m (20,000 feet). The abyssopelagic zone is characterized by darkness and the water is nearly freezing (with temperature of about 4 degrees Celsius). There is no adequate amount of nutrient in this zone and some organisms often feed on sea-floor mud and suspended matter. The fish that lives in this zone usually have exceptionally large mouth and unhinged jaws which they use to scrape food off the sand within the ocean floor. They also use their large mouth together with bioluminescence to catch prey.