Final answer:
The period of civil war following the death of Marcus Aurelius in A.D. 180 led to the decline of the Roman Empire. Hence the correct option is B .
Step-by-step explanation:
Marcus Aurelius, a Stoic philosopher, made his son Commodus his co-emperor, but Commodus' reign was marked by incompetence and debauchery.
The period of civil war following the death of Marcus Aurelius, the last of the five good emperors, began in A.D. 180. Marcus Aurelius was a brilliant leader and Stoic philosopher, but his decision to make his son Commodus his co-emperor led to a decline in the Roman Empire. Commodus' reign was marked by incompetence and debauchery, ultimately leading to his assassination.Hence the correct option is B .