Which of the Following Statements Describes a Feudal Social System

Which of the following statements describes a feudal social system?

A) Serfs cultivated pieces of land owned by nobles, who, in turn, provided military protection for the serfs.
B) Serfs, protected by knights, owned all land and controlled the profits generated in the cultivation of that land.
C) Serfs controlled the government and were supported by the labors of aristocrats who owned and worked the land.
D) Nobles employed serfs to protect their lands against armies of knights who made a living pillaging lands cultivated by the nobles.