Federalism is:
a. not a component of the us constitution.
b. patriotism towards one's country.
c. a system in which two or more governments share power over the same constituents.
d. a system that gives the federal government most of the powers in the country.

I believe the answer might be C:

Federalism limits government by creating two sovereign powers—the national government and state governments—thereby restraining the influence of both. Separation of powers imposes internal limits by dividing government against itself, giving different branches separate functions and forcing them to share power.