John C. Calhoun supported the concept of nullification before the beginning of the Civil War. Nullification is the idea that US states have the right to ignore (invalidate) any law that they deem unconstitutional. This means that if a state thinks that a new law goes against a current constitutional amendment, they have the right to not follow it. The nullification crisis causes severe tension in Congress for decades leading up to the Civil War.
The answers to the question should be B, C, and D. hope this helps
