The correct answers are:
D. All of the above;
The versatility of the soil types and their properties in different regions is a result of multiple factors, including the climate of the place, the amount of rainfall, the topography of the area, as well as the organisms that live there. All of them have contribute in their own unique ways to the soil formation, and what kind of soil it will be.
B. Fragile;
The permafrost soil, also known as gelisol, is a soil type that is very fragile. This type of soil is very thin, it has almost no natural protection, the humus layer is is in the top couple of mm, and it is easily eroded. The slightest disturbance in its surroundings will mean the end of this soil type very quickly.