Answer:
A. The Supreme Court
Step-by-step explanation:
The supreme court is a part of judiciary branch of the government. The judiciary branch has the function to interpret laws on legal conflicts that occurred in united states.
As a form of balance of power, every laws that created by the legislative branch have to pass the examination conducted by the supreme court. The supreme court will check whether the new law violate/contradict the existing constitution. If there is a violation or contradiction, the supreme court has the right to call the new law as 'unconstitutional'.