The Plague of Justinian Provides Evidence of All the Following

The Plague of Justinian provides evidence of all the following except:

A) The interconnectedness of parts of Eurasia and Africa around the middle of the 500s CE.
B) The sophistication of ancient medicine to diagnose the causes of the disease and treat it properly.
C) The impact of climate change as the earth's temperature declined and disease spread more readily.
D) The impact of increased labor costs and food shortages on economies in various parts of Eurasia.