American Association of Medical Assistants (AAMA)
I belive the answer is <span>To assert and maintain their rights
All the rights of American had been guaranteed since the creation of first 10 amendments of the constitution.
In order to preserve true democracy, we could say that it is our duty to </span>assert and maintain their rights so there is no-one could form a tyrannical rule in this country (not even the government itself)
During the 17th and 18th centuries, the frontier for the British colonies of North Americas could usually be found at the "<span>b. Appalachian Mountains" since this was the area that most settlers were not inclined to pass.</span>
The excerpt above expresses how the role of public education in the United States has drastically changed over the course of 100 years. During the middle of the 1800's, school was seen as a privilege to attend, not a guarantee. However, this idea changed significantly over the course of the next 100 years. By the time of the middle of the 1900's came around, attending school was seen as a normal thing to do.
This is why D is indeed correct.