The correct answers are A and C.
Serfom governed economic relationships during the medieval era in Russia. The privileged states, nobility and aristocrats, were landowners. They granted their fields to serfs/peasants, who could cultivate them for a living in exchange for several types of payments to their lords, to whom they had to promise absolute obedience. Hence, serfs were subject to the will of the lords if they wanted to have acces to a piece of land.
In turn, lords promised protection to their vassals, as they were powerful enough to have some military/security forces under their command.
