Answer:
B. Oceania
Step-by-step explanation:
Oceania is not only the smallest ecological zone in the world, it is also the smallest continent in the world, with most of that continent being made up of Australia.
An ecological zone can also be called an ecozone and is characterized by a geographic area, where borders are composed of natural factors that occur in nature and not by factors created by humans. These natural boundaries, separate the regions due to differences in vegetation, soil, fauna, climate and other factors that occur naturally in the environment.