The chemicals used on farms, golf courses, and domestic gardens are often to blame when groundwater becomes contaminated with..

A. Fuel.

B. Sewage.

C. Nitrates.

D. Acid.

The answer is C). Nitrates

Explanation: Animal wastes and nitrogen-containing fertilizers are used to grow plants and they contain nitrates. Nitrogen exists naturally in soils, typically bound to organic matter and mineral soil material. When these fertilizers are used, they increase the concentration of nitrates in the environment, especially in the soil.

d is the logical answer but im not a 100% sure

i'm sure the answer you are looking for would be

a. an ice age

hope this contact me if this didn't or you need with more answers : )