Answer:
D. to ensure that the government doesn't abuse its power.
Explanation:
If one man got to make every single decision of what happened in a certain country, he could do something really bad to get him personal gain and nobody could stop him. If he had other people to help check this power, there would be a smaller chance of him abusing his power. If they don't have a ton of power, they won't be able to do as much damage as if they had unlimited power.
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