Aregion with clearly defined borders is called a

Formal region

Explanation:

A formal region is one that is defined clearly by a structure such as the government. These type of regions have very clear boundaries, and include places such as cities, counties, countries, towns and states. Formal regions can often nest inside one another (a city is within a state, which in turn is located within a country).

c

the articles of confederation placed most of the power on the feds