In the commercial farming, which is used in the developing and well developed countries, there's not really a space for the shifting cultivation, nor there's a real need for that.
The shifting cultivation is mostly practiced in the poor countries, where the subsistence farming is dominant. The purpose of the shifting cultivation is to leave the soil time for recuperation and get back to better fertility levels, and that is done by changing the plants every year, and because every plant is using different nutrients, the soil can be used for longer periods of time.
The answer is B. Shifting Cultivation. This is because shifting cultivation is most commonly used for subsistence farming which is the opposite of commercial farming. Hope this helped if you need any more help feel free to ask
Mountains isolated many groups that migrated to the region. Dense forest served as a barrier to migration across the region. Vast plains facilitated the migration of people across the region.
