Dividing political power between a central authority and other units, like the states in the United States, is the main concept of A. monarchy. B. democracy. C. absolutism. D. federalism.

D. federalism.

Extra: Federalism is a system of government where power is divided between a central authority and smaller political units, such as states or provinces. This division of powers allows for a balance where the central government can address nationwide issues, while the smaller political units can cater to local needs and preferences. In the United States, the Constitution outlines this division of powers between the federal government and the states. A key characteristic of federalism is that both the central government and the subunits have their own areas of authority and can make decisions independently within those areas. This contrasts with a unitary system, where a single central government has ultimate authority, and any regional or local authorities only have powers that the central government chooses to delegate.

Monarchy (A) refers to a form of government where a single person, usually called a king or queen, reigns over a country. Democracies (B), on the other hand, are systems where the citizens have the power to make decisions about their government, often through elected representatives. Absolutism (C) is a form of monarchy where the ruler has absolute power, without checks and balances from other branches of government.