Feudalism faded away because the A
knights were mostly killed off in the Crusades.

B
rise of economies meant that kings could hire warriors.

C
plague killed most of the serfs.

D
serfs led a successful uprising.

 B. rise of economies meant that kings could hire warriors.

Explanation:

The first signs of a modern economy brought about certain changes in the social and political life of Europe. The emergence of economics led to the disappearance of the medieval socio-economic system of feudalism. The king no longer had to give land to the feudal lord to get to the army, and he was since then able to finance military campaigns directly from the state treasury.

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answer; obey the closest relative's wishes;