The correct answer is B. by defeating Germanic invaders
Step-by-step explanation:
Charlemagne, also known as Charles the Great was an important Roman Emperor, although, before this, he was also a King. He was mainly known for unifying the western Roman Empire and for promoting learning and education. This as possible because during his reign he supported literature, art, and scholarship by demanding the creation of books to teach certain subjects, bringing scholars from other countries, supporting the action of monasteries, promoting liberal arts, among others.
However, by defeating Germanic invaders Charlemagne supported the stability and expansion of the Empire but did not promote learning and education as wars ith invaders were not related to education or to the actions of Charlemagne for promoting it.