Which of the following is the most permeable? shale clay gravel nonporous rock

The right option is; gravel

The most permeable is gravel.

Permeability describes how water can easily move through porous soil or bedrock. Gravel is a loose small fragments of rocks that is usually used for laying on the beds of roads, and rail roads. Gravel is grouped into granular gravel, and pebble gravel. Gravel are highly permeable and porous. Gravel can hold a lot of water, and water can flow easily through them.