Answer:
D. king; lords; vassals; serfs
Step-by-step explanation:
The social order at the end of the middle age was hierarchical and statist. Hierarchical because it was very difficult for a person to move from one social position to another. Statistical, because each person assumed a very well defined role in society, generally according to the group in which he was born.
There was a great disparity of income between the richest (Kings and lords) and the poorest (serfs and vassals). Therefore, this society was marked by strong social inequality.