Which is an adaptation?

I don't see any examples, but to help adatation is the process of adapting or being adapted.  

Example: A horses teeth grinding grass

An adaption is any heritable trait that helps an organsim, such as a plant or animal, survive and reproduce in its environment.  

Explanation:

Adaptation is the evolutionary process where an organism becomes better suited to its habitat. ... An example is the adaptation of horses' teeth to grinding grass. Grass is their usual food; it wears the teeth down, but horses' teeth continue to grow during life.

sulfur dioxide

explanation: acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.

i think it’s c but i might be wrong. if i am let me know! have a good rest of your day as well!