Consider the following statements:[Physical Geography]

Statement I: In the context of effect of water on rocks, chalk is known as a very permeable rock whereas clay is known as quite an impermeable or least permeable rock.

Statement II: Chalk is porous and hence can absorb water.

Statement III: Clay is not at all porous.

Which one of the following is correct in respect of the above statements?

The correct option is: Only one of the Statements II and III is correct and that explains Statement I.

Step-by-Step Explanation:
Let us evaluate each statement individually to understand their correctness and logical relationships:

1. Analysis of Statement I:
Chalk is a highly porous form of limestone. Because it is porous and has cracks/joints, it is highly permeable, allowing water to pass through it easily. On the other hand, clay consists of extremely fine particles. While clay has high porosity (it can hold a large volume of water in its tiny pore spaces), the pores are so minute and disconnected that water cannot flow through it easily. Hence, clay is highly impermeable (or has very low permeability). Therefore, Statement I is correct: chalk is a very permeable rock whereas clay is quite an impermeable or least permeable rock.

2. Analysis of Statement II:
Chalk is indeed highly porous. Its structure contains numerous microscopic spaces (pores) that allow it to absorb and store water. Therefore, Statement II is correct.

3. Analysis of Statement III:
Clay is actually highly porous because the total volume of pore space between its tiny clay mineral particles is very large. The misconception is that because clay does not let water pass through (low permeability), it is not porous. In reality, clay has a high porosity but low permeability. Therefore, Statement III is incorrect.

Conclusion:
Comparing our analysis of Statements II and III, we find that:
- Statement II is correct.
- Statement III is incorrect.
Thus, only one of the Statements II and III is correct (specifically, Statement II).
Furthermore, Statement II ("Chalk is porous and hence can absorb water") explains the first part of Statement I (why chalk is permeable and allows the movement/absorption of water). Consequently, this matches the option: "Only one of the Statements II and III is correct and that explains Statement I".