In the following excerpt from the Gettysburg Address, an appeal to _____ is particularly being made.
From the Gettysburg Address It is for us the living, rather, to be dedicated here to the unfinished work which [the brave men] 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 gave the last full measure of devotion—that we here highly resolve that these dead shall not have died in vain. . . .
A authority
B ethics
C attitude
D logic

The speech is making an appeal to ethics, and how many brave men died for a purpose, and it is our duty or duty of the audience to not let that death and suffering be in vain, the speaker wants to fully convince the audience that the sacrifice that the brave soldiers did defeating the confederacy in the same city where they now pay a tribute, and Lincoln calls the public to continue the efforts of changing and moving forward in the reconstruction of the country.