The Institution of Slavery in Complex Societies Likely Resulted from Which

The institution of slavery in complex societies likely resulted from which of the following?

A) Slavery was a regular feature of foraging societies and was easily adapted to more complex civilizations.
B) Slavery was an unfortunate outcome of Sumerian religious beliefs.
C) Slavery was the product of the division of labor common to early cities.
D) Slavery was an outcome of the greater social and class divisions that came with more complex human civilizations.