A. The necessary and Proper Clause
Article I of the U.S. Constitution establishes all the power that the Congress has, such as the power to regulate commerce within the states, provide and maintain a navy, establish post offices, etc. And although it does not specifically state how the Congress shall fulfill those legal powers, the Constitution does have a clause that guarantees that the government carries out all his duties, which it is The Necessary and Proper Clause, it states the following:
"Congress shall have power to (...) To make all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this Constitution in the government of the United States, or in any department or officer thereof."
In the diagram, the first sentence states an enumerated power of Congress, the second one shows the Congress' method to carry out the law.
