Why Is Pollution of Groundwater a Greater Environmental Hazard Than

Why is pollution of groundwater a greater environmental hazard than pollution of surface water?

A) The opposite is true. Surface water is a greater hazard because it is more integrated into our environment.
B) The opposite is true. Surface water moves more rapidly and, hence, is more difficult to treat.
C) Groundwater is much more vast, moves slowly, and is not as accessible.
D) Photosynthetic organisms in groundwater can die off no longer producing the oxygen we need.