Read the excerpt from Abraham Lincoln's Gettysburg Address:

"It is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the great task remaining before us—that from these honored dead we take increased devotion to that cause for which they here gave the last full measure of devotion—that we here highly resolve that these dead shall not have died in vain—that this nation, under God, shall have a new birth of freedom, and that government of the people, by the people, for the people, shall not perish from the earth."

What is Lincoln's purpose in the excerpt?

A. to thank the families of soldiers for their support
B. to describe the varied lives of fallen soldiers
C. to encourage young citizens to enlist in the military
D. to rally emotional support for a unified country