The primary cause of the depletion of the Atlantic cod fishery was overfishing.
Too many people were fishing in the same spot for such a long time, that the cod in these areas became depleted - they couldn't repopulate as fast as the fisherman could fish them.
b. unite North and South Korea under a communist government
It would be "B. corrosive: having the power to eat away or erode" that is not derived from the Latin word coronatus, since coronatus has to do with being "crowned" or "encircled," which does not have to do with corrosion.