The life of a slave was often as unbearable as a life can be. They could not be sure they will not be killed at any instant, without a warning, or tortured, or even forced to torture others.
Some slaves probably favoured death to their fate, and felt that even a slight chance at improvement was worth the risk. Perhaps they hoped they would be either killed or freed, and not tortured, and perhaps they would be tortured anyway by their cruel masters, In a way, for many escape was they only option that offered any sort of hope for a bearable life for them.
The most important reason for the collapse of Rome was the failure to actually integrate what they conquered. When Roman soldiers conquered new lands, it was rare that they ever attempted to force their culture, ideals, or laws upon the natives and barbarians. Thus, when the Empire began suffering internal struggles, the natives they had conquered decided to take action, which lead to the swift collapse by barbarian invasion from all sides. It's hard to pick a LEAST important reason, seeing that there were many of them, but I suppose a contender would most likely be the common refusal of the Empire to even acknowledge that barbarians were rising. On the outer edges of their territory, in places like Gaul and Morocco, the Roman government was reluctant to even recognize the threat of the barbarians, thinking that even accepting that these barbarians were causing trouble would weaken their prestige in the public eye.
The letter D is why it started
He did not approve of slavery, he just didn't know how to end it
The only answer that would make cense for this question is c because the rest of the answers are either false or deal with ww2