Answer:
A) The house of representatives voting to impeach a president.
Step-by-step explanation:
Federalism is a system of government which divided the control over the country into two levels of government: Federal government and Several States government.
Federal government will handle the matters that will influence the nation as a whole while the States government will handle the matters that will influence each individual states.
Under federalism, a country can arrange a system to balance the power between states government and Federal government. In United States, Impeachment is one example of that balance of power. During an impeachment, each states can send out their 2 representatives to examine the evidence for the impeachment and vote to whether keep the current president in office or force the president to quit his/her position.