b.) powers that allow the each branch to curb the others
The enslaved people in Sparta were called Helots.
They were actually the majority of the people in the land dominated by Sparta, according to Herodotus, as many as seven times more than the Spartans.
They worked primarily in agriculture.
The Helots were regularly killed by the Spartans.
D is the answer it prevented the creation big business combining to make monopolies