When Do Central Governments Often Gain Power and Become Either

When do central governments often gain power and become either confederated or federated?

A) when the subunits face collective dilemmas they cannot overcome
B) when a revolution occurs, overthrowing a monarch
C) when factions form, leading to disagreements among constituents
D) when a dictator assumes authority and compels subunit governments to give up power
E) when states fail to pay their taxes owed to the national government