Answer;
C. they seceded and elected Breckinridge as president.
Southern states react to the election of Abraham Lincoln in 1860 is that: They seceded and elected Breckinridge as president.
Step-by-step explanation;
Southern states were not prepared to have a Republican president especially not Abraham Lincoln who raised serious questions about slavery. Lincoln was against the spread of slavery, and made his position in public. Prior to Abraham Lincoln's election in 1860, the southern states had already threatened to secede. After the elections, and by the time he was giving his inauguration speech in 1861, seven southern states lived up to their threats and seceded.