Answer:
A) an overthrow of the government by a tyrant
Step-by-step explanation:
When the legislative and executive branches of government are not separate, this results in a tyrant overthrowing the government.
This is because, the legislature acts as check and balance to the executive by having veto power and also having the power to reject bills made by the executive, rejecting political appointees, etc.
If this power is taken from the legislature there will be a tyrant who can pass any bill into law without obstruction.