The second picture showing big rocks with the gaps between where they touched empty.
Explanation:
The figure shown in picture 2 will be the most porous as it does not comprise of any blocking particles. I t will be well sorted and will allow small molecules to easily pour through it.
On the other hand, the other figures like figure 3 will not have much porosity as the path is blocked by many large and small rocks in the image. Hence, it is not the correct option.
