The answer is B, water easily flows through it.
The word "permeable" means that something can allow other substances (liquids and gas specifically) to flow through. If we describe something as "permeable" or "fully permeable" it means that this thing allows all liquids and gas to pass through it.
Other examples using the word "permeable" are such as "semi permeable" or "not permeable". In these cases, they're describing that the thing only allows certain gas and liquid to pass through only (typically smaller ones in size), and that it does not allow any gas or liquid to pass through at all, respectively.
Therefore, since the soil is permeable, water can easily pass through it, thus the answer is B.