An artisan well is dug upto an impervious layer of rocks.

Answer: Option B

Impervious : not allowing fluid to pass through.
Hidden : kept out of sight; concealed.
Penetrable : allowing things to pass through; permeable.
Hard : solid, firm, and rigid; not easily broken, bent, or pierced.
Dry : free from moisture or liquid; not wet or moist.

Antonym of Impervious is Penetrable