C The coast with lake victoria.
<span>Humans have the ingenuity to use/adapt to another resource when another shows signs of depletion</span>
This Should Help a Little:
A largely semi-arid belt of barren, sandy and rock-strewn land, the Sahel marks the physical and cultural transition between the continent's more fertile tropical regions to the south and its desert in the north. ... The Sahel also suffers from ethno-religious tensions, political instability, poverty and natural disasters.
I'm not 100% sure but I think the answer you are looking for is something like for example; Forest, grassland, tundra, desert, & maybe Ice sheets.