How do people's agricultural practices affect the environment of sub-Saharan Africa?

A. Many farmers practice slash-and-burn agriculture, leading to deforestation and desertification.
B. Many farmers practice slash-and-burn agriculture, leading to long-term improvements in soil quality.
C. Many farmers are nomadic herders, leading to long-term improvements in soil quality.
D. Many farmers are nomadic herders, leading to deforestation and desertification.