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
