Question

Why are grassland and forest soils good for farming?      A. There is not enough rainfall to promote chemical weathering or retaining nutrients.
  B. A layer of permafrost prevents the decay of organic material that enriches the soil.
  C. There is enough water to promote chemical weathering, but not enough to wash away nutrients.
  D. Too much water promotes chemical weathering and washes away nutrients.

Answer 1

The most sensible answer I believe would be C. Grasslands and forests do not have permafrost so B can be eliminated. D is not right because forests and grasslands definitely do not get TOO much rain, assuming they're not talking about tropical rain forests. 

Answer 2

There is enough water...;c