Answer:
Option D, loyalty, is the right answer.
Step-by-step explanation:
In Europe, throughout the middle ages, the state and society were based on the Feudal system. Feudalism was a system in which the king who was on the top of the hierarchy granted a piece of land to people for service. it was a method of structuring society encompassing relations obtained from the holding of land in return for labor or service. In this system, the king gave a piece of land to his subordinates who provided the king with military support at the time of war. In short, this was a system that was based on loyalty.