Final answer:
The correct answer is b. The Vikings' raids led to the rise of local aristocracy for protection as the Carolingian Empire weakened, eventually contributing to European societal transformation and dissolution into feudal systems.
Step-by-step explanation:
The question: Which of the following best describes the effect of the Vikings on mainland Europe? has the correct answer as option b: As the Carolingian Empire fell apart, people looked to local aristocrats to protect them from the Vikings. This period was marked by societal restructuring as the centralized control of the Carolingian Empire diminished, leading to the rise of local feudal lords who provided protection against Viking raids and other threats. During the Viking Age, these raiders from Scandinavia conducted frequent raids across mainland Europe, seeking riches such as silver and slaves, and targeting especially undefended monasteries.
Eventually, the Vikings began to settle and blend into the societies they had once raided. Noteworthy is the establishment of the Duchy of Normandy by Viking descendants and the crowning achievements of Norse leaders like Harald Bluetooth in Denmark, Olaf Tryggvason in Norway, and Olof Skötkonung in Sweden who significantly contributed to transforming Viking society from marauders into part of medieval European civilization. Thus, while Vikings initially brought chaos, they also laid groundwork for new political structures and trade networks—ultimately shaping the course of European history.