Which of the Following Is Correct About National Ambient Air

Which of the following is correct about national ambient air quality standards?

A) All of these standards are set based on protecting human beings.
B) The primary standards are set to protect animal life, and the secondary standards are set to protect plant life.
C) The Environmental Protection Agency sets primary standards, and the states set secondary standards.
D) The primary standards are set to protect human beings, and the secondary standards are set to protect vegetation, matter, climate, visibility, and economic values.
E) The primary standards were set by Congress and the secondary standards are set be the Environmental Protection Agency.