Answer:
C. "The union of these four Presidents carved on the face of the everlasting hills of South Dakota will constitute a distinctly national monument."
Explanation:
In numeral C, Coolidge is describing why Mount Rushmore will be inspirational to future generations.
The reason is that the faces of four of the most important presidents of U.S. history are carved in the monument: George Washington, Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt.
These four presidents had a very important influence in U.S. history because of their political thoughts and actions, and when people visit Mount Rushmore and study American history, they will remember these presidents, and try to act accordingly in some way (according to Coolidge).
