Your answer would be D) Mesopotamians believed in the "eye for an eye" approach to justice. The phrase "eye for an eye" means someone that does something to another person should be penalized in a similar matter. And most of the laws have people's consequences relating to the actions that they made.
The answer is NOT (A) because there were classes during their time period.
The answer is NOT (B) because there were rules, and the rules were from The Code of Hammurabi.
The answer is NOT (C) because in Law #205, it says, " If the slave of a freed man strike the body of a freed man, his ear shall be cut off." But, if it were the opposite way, the free man strikes the slave, the free man wouldn't be as punished like the slave.