What is the medium through which the well is likely to become contaminated based on the information given?

The correct choice of groundwater as the medium through which the well is likely to become contaminated is based on its role as a primary source of drinking water in many regions. Groundwater is stored in aquifers below the earth’s surface, and if contaminants are introduced through various means, such as agricultural runoff, industrial discharges, or improper waste disposal, these substances can seep through soil layers and into the groundwater supply. This process poses a significant risk as groundwater can carry contaminants over long distances, affecting the quality of water available from wells.

In many cases, groundwater is vulnerable to pollution from surface activities; for instance, if toxic substances are released on the ground's surface, they can eventually make their way through the soil and into the groundwater, leading to potential health hazards for communities relying on well water. Understanding this pathway emphasizes the importance of protecting groundwater sources to ensure safe drinking water.

While air, surface water, and soil can also be mediums for contamination, they do not directly lead to well contamination as groundwater does. Surface water can eventually influence groundwater quality but is not typically a direct medium for well contamination itself. Air does not typically transmit contaminants directly to water sources in the context of well contamination, and while soil can act as a filtration medium, it is