The correct option is D Hinterland
A hinterland is the remote areas of a country away from the coast or the banks of major rivers. For example, "the hinterland of southern Italy". Hence, Option C is correct. Among the rest of the options, swamps mean an area of low-lying, uncultivated ground where water collects, archipelago means an extensive group of islands, isthmus means a narrow strip of land with sea on either side, forming a link between two larger areas of land. These options do not express the intended meaning, hence incorrect.