The answer to this question is D.
The neritic zone (option a) is a shallow area of ocean (about 200m in depth) which is essentially the area where the ocean interacts with the coast, although in very rare cases this can be further out to sea dependent on the oceanic plate.
The surface zone (option b) is, as the name suggests, where the ocean and the air meet and therefore not exclusive to the "open ocean" as specified in the question.