I think it's B, if they are geographically around one another and share some racial background they are related. DNA, for example does prove we can be closely related. Genetics and such.
Really hope this helps, tell me if i'm wrong!
they erode rocks and stuff like that
The farmers in the area are mostly subsistence farmers, as the region is very hot, and arid,making agriculture unviable. as a result there is famine and drought in the area, as well as nutritional issues.
Oceanic Crust
Continental Crust
Oceanic crust is denser than continental, this is why continents are at higher elevation than oceans.