When the National Government Gives the States Money to Entice

When the national government gives the states money to entice them to change state laws to match national goals or policies established by Congress,it is:

A) exercising the national supremacy clause
B) an example of layer cake federalism
C) acting through its implied powers in the U.S. Constitution
D) an example of coercive federalism
E) engaged in an exchange deemed unconstitutional by the U.S. Supreme Court in a recent decision