The correct answer is: hierarchical with a defined class structure.
Explanation
Hierarchical with a defined class is the option that best describes Songhai's society.
Moreover, a hierarchy refers to a way of categorization of people in a society based on income, power, education, race or dominance over other people, in which the members who are above are superior or can rule those below them. In this case, Songhai society used to work in that way.
