The economic system where power is decentralized and concentrated in various individuals with large estates, possessing legally bound peasants, is feudalism (C).
The process of feudalization which Japan went through also happened in Europe around mid-first century. With the decline of the Roman Empire power was decentralized and people started living in large estates as peasants working for lords.
The other options are economic systems that only came up in Modern Era so wouldn't be logical to apply them when studying the 1000s.