Feudalism is primarily a political and social system that outlines the relationships between different levels of society, particularly between monarchs, nobles, and vassals, often based on land ownership and allegiance. In contrast, manorialism refers specifically to the economic system that revolves around the manor, the lord's estate, which includes the agricultural organization and the relationships between the lord and the serfs or peasants who worked the land.
Among the given responses, the statement "Feudalism controlled relationships between nobles and monarchs" most accurately highlights a key difference, as it emphasizes the hierarchical nature of feudalism in terms of political loyalties and obligations.