The correct answer is: b) Terrace farming.
Terrace farming is a traditional practice in Nagaland that helps conserve soil. It involves building terraces on the sides of hills to create a series of flat surfaces. This helps to prevent soil erosion and makes it easier to grow crops.
Monoculture is the practice of growing a single crop in a field. This can lead to soil erosion and nutrient depletion.
Intensive tilling is the practice of plowing the soil deeply and often. This can also lead to soil erosion and nutrient depletion.
Chemical fertilizers are substances that are added to soil to improve crop yields. However, they can also pollute water supplies and harm the environment.
Terrace farming is a sustainable practice that helps to conserve soil and protect the environment.