the emissions from volcanic activity the level of pollution caused by people the amount of ozone in the stratosphere the amount of oxygen produced by trees
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: The U.S. Environmental Protection Agency (EPA) was established in 1970 to address problems that existed in the environment. Which is the EPA most likely interested in reducing?
Possibilities:
- the emissions from volcanic activity
- the level of pollution caused by people
- the amount of ozone in the stratosphere
- the amount of oxygen produced by trees

the level of pollution caused by people