The answer is C. keep enough strength in the senate to protect southern interests
Back then, Slavery is almost a way of life of southerners.Back then, the productions amount in northern part of USA is way more than the south. And the Northerners did that without slavery
In 1808 , the congress abolished slave trading with Africa, making the economic difference between the south and north separated even further
In order to protect their own interest, they want slavery to extend to the north so they have enough strength in the senate to protect its legality
I don’t know what type you need but you could watch if you have Netflix the docuseries evil genius, when they see us, murder to mercy: the cyntoia brown story, worlds most wanted, or the social dilemma. For school I would probably watch the social dilemma because it’s more of a current thing that you might be able to relate to more and explain it more thoroughly. But if you go under the documentary genre on Netflix there are so many more to choose from. All the examples I listed are on Netflix but you might be able to find some of them on websites like myflixer.to if you don’t have Netflix.
You said it's free response and all we had to do was answer so here's me doing the bare minimum. Lol.