Option 1 -> Mid-Oceanic Ridges are underwater mountain ranges formed by tectonic activity, significant but cover less area than deep sea plains.
Option 2 -> Deep Sea Plains (Abyssal Plains) are vast, flat regions covering approximately 40% of the ocean floor, making them the most extensive relief feature.
Option 3 -> Seamounts are isolated underwater mountains that don't reach the surface, relatively smaller features compared to plains.
Option 4 -> Submarine Canyons are steep valleys cut into the continental slope, representing narrow, linear features rather than extensive areas.
Hence, Deep Sea Plain -> They are the largest and most extensive topographic features on Earth, covering more area than any other ocean floor feature and representing the true ocean basin floor -> correct