While a parliamentary government may be used under a unitary, federal, or confederal system, it primarily differs from governments in which the executive and legislative branches are separate by virtue of which of the following selections?

Following archduke franz ferdinand's assassination, austro-hungarian leaders: a. aided the ottoman empire in its campaign to keep serbia under its control. b. executed nearly all prominent serbs living in austria-hungary c. threatened to invade serbia if serb leaders did not agree to a set of strict demands. d.. formed an alliance with great britain to protect austria-hungary from future attacks.