During a special state convention in December of 1860, South Carolina voted to 1ban slavery from the state.
2declare its support for Abraham Lincoln.
3affirm its support for popular sovereignty.
4secede from the Union.

Secede From the union :)

Explanation:

I think that is the answer. I think

according to classical republican political theory, which democratic republics would function best?

a.   small republics, with people who had similar interests

b.   large republics, with people who had competing interests

c.   republics made up entirely of landowners

d.   republics made up entirely of servants