The answer is domestic system
They were all slave states that had remained in the Union and this is what Missouri, Kentucky, Maryland and Delaware had in common during the Civil war. The correct option among all the options that are given in the question is the second option. I hope that this is the answer you were looking for and it helped you.
A representative government, economic equality for all, and exchange of land for service and protection of individual rights
C allow citizens to vote in elections I think. I know it's not D
