What is essential for a confederation? smaller political units maintaining their sovereignty

the establishment of a mixed economy

a large amount of territory

severe restrictions in the sovereignty of each citizen

smaller political units maintaining their sovereignty

Explanation:

Confederation is the name given to a country that is a federation, but the states that make up that country maintain their sovereignty, separate from the power of the federal government. In this case, to maintain a confederation it is essential that the smaller political units, the states, maintain their sovereignty. This is different from a federation, because in a federation, states lose sovereignty, transferring it to the federal government.