Which of the following would reduce water tables? question 7 options: overpopulation flood snowmelt water pollution

The most appropriate answer is overpopulation. By water tables, I am assuming you mean the groundwater table. Humans extract a lot of groundwater in many regions, particularly for agriculture, which can reduce groundwater levels. Urbanisation can result in more impervious ground, such as roads, which reduced the amount of water filtering through the soil (groundwater recharge). Snowmelt and floods are more likely to lead to greater groundwater recharge, and water pollution changes the quality of groundwater, rather than quality. 

Very hard to understand