The correct answer is letter B.
Explanation: Federalism is a political system in which political organizations (states, provinces) or groups come together to form a broader organization such as a central state. In the federalist system, its member states maintain autonomy.
A good example of federalism is the United States of America. The states unite to form the central system, but have the autonomy to define issues of various natures, such as the creation of laws, the definition of public policies, the creation and collection of taxes, etc.