By what authority do local governments exists?

A.) the federal legislative powers

B.) the eighth amendment of the constitution

C.) the tenth amendment of the constitution

D.) the state constitution and government

Local governments exists by the authority of C.) the tenth amendment of the constitution.

Explanation:

The Tenth Amendment to the United States Constitution (1791) clarified the principle of federalism and defined rights that belonged to the states.

In particular, that federal government was invested only with the power assigned to it by the Constitution, while all remaining powers belong to the states, making local government matter of the states as well. Following the amendment, states have introduced different systems of local governance. Currently, they include the following categories: County Governments, Town or Township Governments, Municipal Governments, Special-Purpose Local Governments.