First off, the controversy of this had led to an imbalance in congress among the number of free states and slave states. So this rules out our first option. Due to it not being all of the above, that's our fourth answer ruled out as well. The Webster speech did not happen for 10 more years so it is very unlikely that this is what led to that speech. Even without the process of elimination, it would be B because the Missouri Compromise admitted Missouri as a slave state and Maine as a free state in order to preserve the balance of power in congress. Also, Henry Clay (the Great Compromiser) drafted this.
North and South Carolina became separate colonies in 1712. Each of the colonies prospered on its own affair without depending on the other. The fertility of the Low Country and several harbors facilitated the prosperity of the South.
