Explain the differences between interpretation a and interpretation b

you work at weenie hut juniors if you answer this question

1. it was caused by feudalism

2. charlemagne used christianity as a major cornerstone for his rule. cloisters were built all over the empire to act as centers for the (re)population of the vast european wilderness.

3. the europeans feared the next raid every time chetak

i'm not so sure about #6. but i hope i you with the first 3.