Answer: C
. a decrease in Native Americans as smallpox spread, but an increase in Spaniards as they continued to colonize.
Explanation:
Looking at the picture one can see that those affected by the smallpox are Native Americans but the Spanish person in the picture is fine. This mirrors real world events because the exploration of the Americas by the Europeans brought European diseases that the inhabitants of the Americas did not have immunity to.
It is estimated that Native Americans who died from smallpox were about 90% of the population. This enabled Europeans like the Spanish - who already had immunity for the most part - to colonize the continent much more easily.
If the Spaniards did not infect the Aztecs with small pox, the aztec population wouldn't have declined so quickly and their would have been more outer breeding.