The correct answer is option 1: Artesian well. An artesian well is a type of well in which water naturally flows to the surface without needing a pump. This occurs because the water is under pressure from an underground aquifer. The pressure is created by the weight of water in a confined space, such as a permeable rock layer. When a hole is drilled into the aquifer, the water is forced upwards and can reach the ground surface.
Option 2, a spring, is a source of water where water naturally discharges from the ground. Unlike an artesian well, springs do not rely on pressure from an aquifer.
Option 3, a hot spring, is a type of spring where the water is naturally heated by geothermal energy.
Option 4, a geyser, is similar to a hot spring but erupts periodically, shooting hot water and steam into the air.
Therefore, the correct answer is option 1, an artesian well.