The ground water that occurs when flow of the subterranean water is not confined by the presence of impermeable layers is called

unconfined groundwater
confined groundwater
aquifer
artesian

The correct answer is A. unconfined groundwater.

Unconfined groundwater is groundwater that is not under pressure from overlying material. It is the water that occurs in the saturated zone above the water table. The water table is the surface below which the ground is saturated with water. Unconfined groundwater is free to move and flow through the pores of the soil and rock. It is the source of water for wells and springs.

Confined groundwater is groundwater that is under pressure from overlying material. It is the water that occurs in the saturated zone below the water table and above an impermeable layer of rock or soil. The impermeable layer prevents the water from moving freely. Confined groundwater is often found in aquifers. An aquifer is a layer of rock or soil that can store and transmit groundwater.

Artesian groundwater is a type of confined groundwater that is under pressure from overlying material. The pressure is so great that the water can rise to the surface without the need for a pump. Artesian groundwater is often found in wells.

I hope this helps!