The correct answer is B) There were deep political divisions in 1860.
The statement about U.S. History that is proven is "There were deep political divisions in 1860."
The political division in the country accentuated with the Presidential election of 1860 that was won by Republican Abraham Lincoln 180-72 in the electoral to his rival John Breckenridge. By that time, the United States was so divided between southern states that clearly favored slavery because their economy depended so much on slaves to work in the large plantations to produce crops and the northern states that pressured to end slavery.