Which of the following is the best definition for feudalism?

Feudalism is the denomination of the predominant political system in Western Europe of the middle centuries of the Middle Ages (between the 9th and 15th centuries), and in Eastern Europe during the Modern Age, characterized by the decentralization of political power; based on the diffusion of power from the top (where in theory were the emperor or kings) to the base where local power was exercised effectively with great autonomy and independence by an aristocracy, called nobility.