Which of the Following Examples Illustrates Devolution?​

Which of the following examples illustrates devolution?​ 

A)  The federal government of Nosterdim handing over the right to appoint governors to its state governments​ 
B) The nation of Debster withdrawing from the economic union of which it has been a member for more than five decades 
C) The government of Pokolistan stepping in and denying the right to vote for certain special case citizens in its state of Jumsta 
D) The states of Kinlo and Vovlin signing a joint agreement to protect water resources shared jointly by them 
E) The national government of Grentia getting dissolved as a result of a constitutional amendment