D. The Kansas-Nebraska Act states that slaves were only allowed in the states below a certain point. And that the number of slave states and free states must remain equal.
A.
abolitionists in free states such as Massachusetts
The new England colonies practiced mainly subsistence farming, middle -> wheat, and south -> plantation farming with huge production. Many people fled to new england for religious freedom but when they got there each colony mainly had their own strict religious beliefs, for example Massachusetts bay.