Final answer:
In the 1860 presidential election, John Breckinridge received the most support in the Southern states (C).
Step-by-step explanation:
John Breckinridge received the most support in the Southern states during the 1860 presidential election due to his strong advocacy for states' rights and the preservation of slavery, aligning closely with the sentiments prevailing in the South at that time. His affiliation with the Southern Democrats, who staunchly defended slavery, resonated deeply with voters in the Southern states.
Breckinridge's platform directly addressed the concerns of the South regarding slavery's expansion into new territories, solidifying his popularity in the region. Consequently, his candidacy predominantly appealed to and garnered significant backing from the Southern states, reflecting the division and polarization existing within the country over the issue of slavery leading up to the Civil War.
In summary, John Breckinridge's primary support came from the Southern states due to his alignment with pro-slavery sentiments and strong advocacy for states' rights.
Correct answer: C. Southern States