Answer:
The statement which best describes the overall claim is:
D. Protecting the environment is essential for maintaining Americans' quality of life.
Step-by-step explanation:
According to the passage from President Carter's letter, there should be concern over how the environment is being affected by pollution as well as programs that help deal with that problem and help preserve nature. The reason for that concern is that the way the environment is affected reflects back on the quality of life of all the American people. Environmental protection means our own protection as well. With that in mind, we can choose letter D as the best option: Protecting the environment is essential for maintaining Americans' quality of life.