Answer:
(D) there was a religious upsurge as a result of social and economic problems.
Explanation:
At the end of the Classical Age, "there was a religious upsurge as a result of social and economic problems."
This is true in the sense that the classical age which lasted between the 8th century BC and 6th century AD was based majorly on the Greco-Roman world civilization.
This classical period was followed by the Middle Age period in which there were various socio-economic problems such as mass migration, invasions, rise in religions (including Christianity and Islam), war, and diseases such as the Black death.
