Answer:
C. The Necessary and Proper Clause.
Step-by-step explanation:
The Necessary and Proper Clause, known also like the elastic clause, is the Clause 18 of Article 1 of the US Constitution, this clause provides the Congress the power that it needs to fulfill its legal powers. Since the 11th Amendment can be abrogated by the Congress, the Congress does it under the necessary and proper clause. To do so, Congress has to express its intent unequivocally and it must have acted pursuant to a valid exercise of power.