A

C. The clause deals with specified powers that are ambiguous and misinterpreted.

Explanation:

The Necessary and Proper Clause, located in Article I, Section 8 of the Constitution, that gives the Congress to power to make any laws that are “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.” As it is contained within the Constitution, the text cannot be changed easily, which forces Congress to settle on an interpretation.

Necessary and proper doesn't mean whatever we want.
An Argument Against Broad Interpretations of the Necessary and Proper Clause (Source: http://tenthamendment.wpengine.netdna-cdn.com)

As can be seen in the text, the powers described in the clause are not clearly defined. Debates over the interpretation have been ongoing since the time of Thomas Jefferson and are still not over.

Different applications of the clause would change the implied powers of the Congress and individual states, but the debates concern the interpretation of the text. The document is supposed to be the foundation of the United States and resist interest-based arguments.