What 2 factors drove the relationships that led to a feudal society?

Good Morning!
 
Two fundamental factors for the formation of the feudal mode of production were:
 
1. The fall of Rome: with the arrival of the barbarians, their lifestyle was implanted in the Italian peninsula and almost all the west, thus, agriculture gained strength and became a source number one income.
 
2. The decline of trade: with the end of the Roman Empire, also trade, once strong, became ineffective. Now agriculture was not only the sole source of income, but it became the sole source of survival, which motivated the formation of the social structures of feudalism. Hugs!

Ithink the answer is c