The correct answer is C. One of the first amendments added after the Bill of Rights protected states from being sued by citizens of other states.
The Bill of Rights of the United States is the collective name given to the first ten amendments of the Constitution of the United States approved on December 15, 1791.
The Eleventh Amendment to the Constitution of the United States (the first amendment after the Bill of Rights), which was ratified in February of 1795, gives each State sovereign immunity against lawsuits in federal courts by someone from any other state or country. It was adopted in response to, and with the intention of nullifying, the decision of the Supreme Court of the United States in the Chisholm case against Georgia.