The correct answer is A) State's Rights.
All of the aforementioned laws dealt with the issue of states rights. For example, the Missouri Compromise established the 36'30 parallel. This parallel would be used to determine what new territories added by the US would be allowed to have slavery.
Another example of this would be the Kansas Nebraska Act. This law allowed citizens of Kansas and Nebraska to vote on whether or not their respective state would allow the institution of slavery. This gave state's more rights over their institutions and laws.
