Which statement best describes how federalism in the united states has changed over time?
a. the u. s. system of federalism established by the constitution was called cooperative federalism.
b. over time, the u. s. system of cooperative federalism has been replaced with a system of dual federalism.
c. over time, the u. s. system of dual federalism has been replaced with a system of cooperative federalism.
d. the u. s. system of federalism has remained the same since the founding of the country.