Which factor most contributed to the violence that newspapers referred to as “Bleeding Kansas”?

A. abolitionists’ attacks on the owners and overseers of new slave plantations in Kansas

B. the use of federal troops to break up protests by both abolitionists and pro-slavery groups

C. conflict between abolitionists and pro-slavery groups to win the slavery vote in Kansas

D. slave uprisings in Kansas that were fueled by arms shipments from radical abolitionists