Based on Webster's words, many southerners would have most likely concluded that: C) the possibility of compromise on the issue of slavery still existed.
What happened here
Senator Daniel Webster's quotation from 1850 suggests that he believed in the unlikelihood of dividing the United States into separate free and slave-holding states due to various reasons.
Southerners, who were proponents of slavery, would likely interpret Webster's words as implying that there was still a possibility of compromise regarding the issue of slavery within the Union.
Webster's statement emphasizes the inherent connections and ties between the northern and southern states, citing "natural causes" and "social and domestic relations" that bind the nation together.