The correct answer is: a) Clearing land, burning, cultivation, and fallow periods.
Jhum cultivation is a traditional form of shifting cultivation practiced in the hills of Southeast Asia. It involves clearing a piece of land by slashing and burning the vegetation, then cultivating it for a few years before abandoning it and moving on to a new plot. This allows the land to recover its fertility and prevents soil erosion.
Option b) is incorrect because intensive monocropping with fertilizers is a type of agriculture that is not sustainable in the long term. It can lead to soil degradation and pollution of water resources.
Option c) is incorrect because permanent cultivation on the same plot can also lead to soil degradation and pollution of water resources.
Option d) is incorrect because large-scale mechanized farming is not a traditional form of agriculture. It is a more recent development that is often associated with the use of pesticides and herbicides, which can have negative environmental impacts.