Because the framers of the US Constitution were concerned about citizens having too much power, they: 1-banned citizens from voting

2-organized a system of consuls and magistrates.

3-established a republic

4-created a system of independently governed city-states.

The answer is they established a republic.

Explanation:

Why would they do this?

Well they thought that a pure democracy was just to hard to keep up with. They thought that every citizen having to vote on every law would just be too hard. They thought our country was just too big for that to work. The second main reason this happened wad because they knew that there was going to be a mix of governing the individual states and governing the country as a whole. This made them think that a pure democracy would just be to hard to keep up with. So they went with a republic which means that every US citizen has a vote but not on laws and stuff like that they vote on the people who make the laws and vote on them.

i beleive that d is the right answer