The correct answer is - Canterbury Plains.
The big island, or rather continent, Australia, has multiple physical regions on its territory, unique and interesting, and some of the major ones are the Western Plateau, the Eastern Highlands, and the Central Lowland. In general, these three large physical regions define the basics of the Australia landscape, and the further divisions from natural, or climatic perspective.
The Canterbury Plains, on the other hand, are not part of the Australian landscape, but they are part of the landscape of the country located on the southeast from Australia, New Zealand. The Canterbury plains are located in the Canterbury region of the country, more specifically, in its southern part.