The correct answer is - D. The farmer would plant cover crops, leave them to die over the winter, and let them serve as natural fertilizer.
A poor farmer in a very poor country is very limited in its options and finances in order to protect the soil leaching. Since the farmer will not be able to buy expensive fertilizers, be it because of finances or availability, the logical solution will be to use the natural way of protection and fertilization.
The farmer will plant cover plants, that will not compete with the primary plants, and also will hold the soil tighter with their root systems. The cover plants will be left there to die out in the winter, and as they die out they will start to decompose, thus providing the soil with the much needed nutrients.
