The correct answer is: "B: The spread of epidemic diseases".
The arrival of European settlers that started with the quest of Cristopher Columbus, brought a disruptive effect to the civilizations that lived in the territories of South, Central, and North America. Besides the economic and social effects, represented in the form of trade and religion, the arrival of colonizers also exposed the locals to new diseases which they were not ready to treat themselves against. This was one important cause of deaths during this period.