Question

how did charlemagne approach unification of western europe after defeating the saxons?
he allowed the saxons to control their local governments.
he took the title \mayor of the palace.\
he forced the saxons to convert to christianity.
he banned the study of greek and latin.

Explanation:

Charlemagne was a devout Christian. After defeating the Saxons, he saw religious unity as a way to unify his realm. Forcing conversion was a means to create a more homogeneous religious - cultural base. Allowing Saxons to control local governments would not be a unification measure. "Mayor of the Palace" was a title from an earlier period in Frankish history (before Charlemagne's significant rule). Banning Greek and Latin study contradicts his efforts to promote learning (Carolingian Renaissance).

Answer:

He forced the Saxons to convert to Christianity.