The statement that accurately compares feudalism and manorialism is:
Both subjected serfs to hard labor under the control of a landlord on an estate.
Feudalism primarily refers to the social and political system where lords owned land and granted it to vassals in exchange for military service, while manorialism focuses on the economic system of the local lord's estate, where serfs worked the land and were subject to the lord's authority. Thus, both systems involved the exploitation of serfs, but they serve different roles in the broader context of medieval society.