Read the following excerpt from President Jimmy Carter's inaugural address in 1976:
Two centuries ago our Nation's birth was a milestone in
the long quest for freedom, but the bold and brilliant dream
which excited the founders of this Nation still awaits its
consummation. I have no new dream to set forth today, but
rather urge a fresh faith in the old dream.
Why does Carter most likely use the word 'milestone?
A To focus on how far the nation has come since its founding
B. To suggest that the nation's birth was one in a long series of steps
C. To underscore how exciting the nation's creation was for the
founders
D. To imply that the nation's creation was an idea that has not yet
been truly realized