In 1860, the southern states highlighted in red would have been least likely to

I believe the answer is: vote for Abraham Lincoln for President of the United States.

The southern states at that time was the major supporter of slavery since its really crucial for their economy. Abraham Lincoln on the other hand, was the major supporter of the establishment movement that want to eliminate all form of slavery from united states.

i can try to solve it just show the graph.

a is correct

hope this let me know if it is right