Concept:A spring is a natural point where underground water rises and flows out from the earth’s surface.
Explanation:Springs occur when groundwater stored in porous and permeable rocks, such as limestone, is forced to the surface.
Limestone allows rainwater to seep through joints and cracks, where it accumulates underground.
When the water table meets the land surface, the trapped underground water naturally flows out as a spring.
This is why a spring is best described as an outlet for underground water in limestone areas.
Rainwater is only the source of recharge, not the stored supply itself.
Rivers and surface streams are not released through springs.
Answer:C — underground water in limestone.