Please answer with explanation

The Supreme Court declares a law Unconstitutional

Explanation:

The Judiciary is one of the three branches of the government in the United States and as per the principle of checks and balances in the U.S. Constitution, are empowered to ensure that the actions of the other two branches do not go against the Constitution.

They can do this through the process of Judicial Review which is described above. By this process for instance, the Supreme Court can declare a law to be Unconstitutional which would render it null and void. They can do this for both national laws and state laws as well.

D. The Supreme Court declares a law Unconstitutional

Explanation:

Because it is the "Correct Answer"