I believe it is D) It suffered a weakening economy, domestic revolts, and a loss to the Allies in World War I.
B - the Church rejected them as heresy.
The works of Greek thinkers were not in line with the dogma of the Church. For that reason they rejected what the Greek thinkers of their time did and called every work which they did heresy not to be read.
Competition was behind the industrial revolution as various companies competed for customers. Thanks to the Industrial Revolution, customers could more easily access goods. Things that had been considered more luxury items could now be had by anyone as more could be made faster, cheaper, easier, and business owners didn't have to employ as many workers. Businesses also had to compete for raw materials sometimes. Others competed for ideas and patents to create various things.