The correct answer is option D, Unconfined aquifers are found between two layers of impermeable soil or rock.
Explanation:
An unconfined aquifer is not confined by rock layer on both of its side. Usually the ground water level (GWL) is considered as the upper layer of unconfined aquifer. Also the rocky layer found on the other side of the unconfined aquifer is not impermeable as the major source of recharge of unconfined aquifer is the seepage of water through is permeable layer or through rain.
