Answer:
B. The law allowed these two new territories to vote on whether or not to allow slavery.
Step-by-step explanation:
The controversies of the Kansas-Nebraska act began when the voting commenced to allow or abolish slavery in these territories. Many people that were pro-slavery went into the states and voted for slavery to be legal. This action caused the election to allow slavery in Kansas. Many abolitionists (people who were against slavery) felt the election was unfair due to the cheaters who visited the state just to cast the vote in favor of slavery.