The most accurate evaluation of the impact of feudalism after the fall of Western Rome from the provided options is:
Feudalism was an effective protective measure against Germanic tribes.
Feudalism arose as a social and economic system in Medieval Europe partly in response to the instability and invasions, including those from Germanic tribes. It provided localized protection and governance through a system of lords and vassals, allowing communities to defend themselves in a time marked by fragmentation and insecurity after the collapse of centralized Roman authority. The other statements do not accurately reflect historical consensus regarding the origins and impact of feudalism.