This Graph Shows an Increase in the Number of Species

This graph shows an increase in the number of species of pesticide-resistant insects from 1900 to 2000.
-How did this increase in resistant species occur?

A) Insects became more prevalent during the 1900s.
B) Insects that were killed by pesticides did not have offspring, but those who were resistant did.
C) Pesticide use promoted genetic changes that caused new species to arise.
D) Insects needed to survive pesticides, so they gained new mutations for resistance.