Federalism is a mixed form of government in which power is shared, ideally equally, between a central (federal) government and region (state) governments.
Federalism generally reduced the rights of the states, since they became actors within a federal system and limited in their powers, rather than operating as their own distinct entities.
The correct answer is D) Compromise of 1850.
The Compromise of 1850 was a law that would temporarily settle the conflict over whether or not slavery would exist in the new territories gained after the Mexican-American War. The Mexican-American War saw the United States gain control of modern day California, New Mexico, Utah, Arizona etc.
At this time, the issue of slavery and its expansion was a hotly debated topic. This is due to the fact that Congressmen from slave states wanted these new territories to allow slavery. While the Congressmen from free states did not want slavery to expand. This is because expanding the institution of slavery would result in an imbalance of free and slave state representatives in Congress.