Which statement best explains how the Kansas-Nebraska Act contributed to the tensions between the North and the South that led to the Civil War ?. a- The act gave abolitionist leaders enough seats in Congress to outlaw slavery throughout the United States.. B-The act allowed state governments to prevent fugitive slaves from being returned to their owners in the South.. C-The act led to violent conflicts between settlers in the Great Plains over the issue of expanding slavery to new territories.. D-The act prevented Southern slave owners from taking their slaves into federal territories without