Despite their frequency in the intertidal zone, in tide pools, sea urchins can be found at many different depths and in any habitats. They can also be found in nearly any ocean temperature. Sea urchins inhabit the polar seas as well as the warm tropics.
Let's eliminate this one by one.
Animal cell does not have walls. So we can eliminate The third option.
Plant cells does have walls, but they also have well-defined nucleus. So we can eliminate the second option
The leave : A. Prokaryotic as the answer
hope this helps
Secondary since plants/animals already lived there, but got killed/driven out of the area they lived/thrived in/on.