Answer:
I believe it is the Holy Roman Empire was one of them which took place in 950–1200 and Carolingian Empire which took place in 800–888
Explanation:
The Holy Roman Empire was regarded as one of the earliest roots of the European government because they had one of the earliest forms of democracy. I'm not sure about the Carolingian Empire but I think they were significant. I hope this helped
The answer is (B) because they believed that slavery would be a local option called popular sovereignty.
