Answer:
a- reserves to the states any powers not delegated to the national government.
Step-by-step explanation:
The Tenth Amendment of the United States Constitution states that any powers that are not specifically delegated to the federal government by the Constitution, nor prohibited by it to the states, are reserved to the states or to the people. This means that the federal government only has the powers that are explicitly granted to it by the Constitution, and all other powers are left to the states or to the people. The Tenth Amendment is often seen as a way to limit the power of the federal government and to ensure that the states have a significant role in governing the country.