In a General Sense, How Is the Nature of Federalism

In a general sense, how is the nature of federalism shaped?

A) Federalism is shaped by governmental actors and how they handle technological developments.
B) Federalism is shaped by the president and his executive cabinet following the inauguration.
C) Federalism is shaped by the Supreme Court and various decisions on cases.
D) Federalism is shaped by how the American people vote in midterm and presidential elections.