Which of the following best explains why south carolina wanted to secede from the union?
a. south carolinians disagreed with northerners, who believed dred scott should have won his freedom.
b. south carolinians believed that abraham lincoln was not qualified to be president.
c. south carolinians disagreed with northerners, who refused to let jefferson davis run for president.
d. south carolinians saw abraham lincoln as a threat to the institution of slavery.