Besides the United States Under the Articles of Confederation,what Is

Multiple Choice

Besides the United States under the Articles of Confederation,what is another example of a confederate system of government where the subunits of government retain sovereignty and virtually all government powers?

A) the United States under the original Constitution of 1787
B) the United States today under the Constitution of 1787 as amended
C) the United Nations and its member states
D) the United Kingdom
E) Japan after the revision of its constitution in 1947