How did the election of 1860 lead to southern states seceding?

a. the democratic party splintered into two groups, northern democrats and southern democrats.
b. the election was so close it led to a divisive recount that southern states believed had suffered from tampering.
c. the republican candidate, abraham lincoln, was elected without winning any southern electoral votes.
d. the whig party did not nominate a presidential candidate for the first time in its history.