Answer: B. Citizens rioted out of anger at Emperor Justinian
Step-by-step explanation:
The rightful statement to follow would be the Nika riots where citizens rioted out of anger against Justinian due to corruption and increased taxation. They were controlled behind the scenes by rebellious nobles and senators.
Justinian put down the revolt by killing more than 30,000 rioters and regained control.
Option A would be wrong because this happened many years after Justinian. Option C happened before the Byzantine empire was formed and therefore before Justinian and Option D happened around the time of option A.