Which of the following definitions best describes the term devolution?

I believe the answer is:  the breakup of a state into smaller, independent states
In devolution, A central government would delegate its authorities to smaller states in order to ensure that it covers all citizens that live in that country,
This method of government usually could only be found in countries with large number of populations and territories.

Ongoing civil wars western roman empire finally collapsed476 c.e. romulus, the last of theroman  emperors in  the west, was overthrown by the germanic leader odoacer, who became the first barbarian to rule in rome. the order that the  roman empire  had brought towestern  europe for 1000 years was no more.

Ghana, first of the great medieval trading empires of western africa (fl. 7th–13th century). it was situated between the sahara and the headwaters of the sénégal and niger rivers, in an area that now comprises southeastern mauritania and part of mali.