Answer:
The correct answer is a) The emperor was among the highest authorities in the Byzantine church.
Step-by-step explanation:
During the Middle Ages, you can identify the Byzantine Empire; was located in the east of the Roman Empire, having as capital the city of Constantinople.
Its emperor was Justinian; the emperor was the most influential figure in the Byzantine church; his orders were to be followed or had a consequence.
For example, in the passage mentioned, the emperor dictates to priests and bishops that they should say their prayers aloud to increase devotion and appreciation for the faithful if they will not be punished on the day of judgment. This is why the passage indicates that the emperor was one of the highest authorities in the church since he could impose orders on priests and bishops.
I hope this information can help you.