The service that completes the Venn diagram is: C. Make marriage laws.
The service completing the Venn diagram is making marriage laws. While both national and state governments have distinct powers, regulating marriage falls under state authority. States govern marriage laws, defining requirements and legalities, highlighting the intricate balance between national and state responsibilities.
This division aligns with the principle of federalism, enabling states to manage social and civil matters, such as marriage, while the national government handles broader issues. The Venn diagram underscores the cooperative yet separate roles of national and state governments, emphasizing their shared responsibilities and distinct spheres of influence in the governance of the United States.
Option C is correct.