Correct Answer - Option 4 : (i), (ii), (iii) and (iv)

__Explanation__

**Permeability depends on both soil properties and Fluid properties**

The kozney – Carman equation is quite useful, it reflects the effect of factors that affect permeability

\(k = \frac{{{\gamma _w}}}{\mu } \times \frac{{{e^3}}}{{1 + e}} \times D_{10}^2\)

Where,

D10 is effective grain size

e is the void ratio

μ is viscosity , γ w is unit weight of water

**a) Grain size:** The coefficient of permeability includes D102, where D10 is a measure of grain size

If the void ratio is the same then permeability is more in coarse soil than in the fine soil

**b) Void ratio: **From the equation, it is clear that k ∝ e2

If the particle size is the same, then loose soils are more permeable than dense soils

**c)** **Degree of saturation**: Permeability is directly proportional to the degree of saturation

**d) Particle shape**:

It is expressed in terms of specific surface area and permeability relates to specific surface area as ‘k ∝ 1/S2 ‘

**e) Adsorbed Water**

Adsorbed water is the water layer formed around the soil particle especially in the case of fine-grained soils. This reduces the size of the void space by about 10%. Hence, **permeability reduces.**