PLEASE HELP ASA One of Charlemagne's most important achievements was:
A. reducing the power of the Catholic Church.
B. uniting much of Europe into a single empire.
C. giving peasants more rights under the feudal system.
O D. stopping the spread of the Black Death in Europe.

The correct answer is "B" "uniting much of Europe into a single empire"

Explanation:

He concurred most of Europe. So it makes sense.

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.

i would go with the last one