Answer:
Correct answer is c . Giving them land so they could pay for their war equipment.
Step-by-step explanation:
Option A is not correct as although Christianity was official religion in the Empire, people were not forced to practice it.
B is not correct as him and lords had the most land.
C is correct as they were his vassals, and Charlemagne realized the importance of this.
D is not correct as this would just provoke rebellions.