Answer:
A. Ethos, because Eisenhower is appealing to the nation's responsibility to continue to do what's right around the world
Elucidation:
In this excerpt from his speech, Eisenhower is employing the rhetorical appeal of ethos by referencing America's values and responsibilities as a free and religious people. He is underscoring the nation's duty to maintain peace, foster progress, and enhance liberty, dignity, and integrity. His mention of the consequences of failure appeals to the audience's sense of responsibility and moral integrity, which is a characteristic of ethos. The other options don't correctly apply: kairos refers to the right or opportune moment to persuade, which isn't clearly invoked in this excerpt; logos pertains to the use of logical arguments or statistics, which aren't present here; pathos is about evoking emotions, and while there's a mention of "grievous hurt," it's not the primary appeal in this excerpt.