1. d. Postal offices.
The Necessary and Proper clause refers to the following clause of the U.S. Constitution found in Article I, Section 8:
<em>The Congress shall have Power ... 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. </em>
This clause enables Congress to have implied powers, that is to say, to have powers that are nowhere stated in the Constitution, but that are necessary and proper to effectively enforce their expressed powers (The powers that the Constitution explicitly grants to the government).
Options a, b and c are all examples of the Necessary and Proper clause (and thus, of implied powers) because those powers are nowhere stated in the Constitution. "To establish postal offices," on the other hand, is not an example of the Necessary and Proper Clause because it is stated in the Constitution (Article I, Section 8).
2. a. Article I.
Section 8 of Article I outlines both expressed powers (such as the power to tax, coin money, establish roads, raise and support armies and declare war) and implied powers (Found in the Necessary and Proper clause).
