Answer:
D.) The Constitution
Step-by-step explanation:
The laws held in each state are important, but they must abide by the Constitution.
The Declaration of Independence was just a letter written by the colonists to the British monarchy.
The orders of the President can be overturned by Congress. There are many systems in place that can challenge what a President says.
The Constitution is the rulebook which all laws stem from. The Supreme Court settles cases based off of this text. This makes it the "law of the land".