Answer:
A.
Step-by-step explanation:
Desertification is the process of ecosystems becoming desert-like. This is often due to unsustainable farming and erosion that strips the lands of its nutrients, leaving it barren and sandy.
The answer choice that represents this process is A, "the change of rich and useful drylands into much less useful deserts."
This shows the rich dryland has become a desert, i.e. desertification