The correct answer is option C, Mutations have arisen that may have altered allele frequencies
There have been several instances where mutation in the gene of an insect is caused due to the harmful external environmental condition which are either created or occurs naturally. Usually, the organisms evolve themselves to sustain in an adverse environment condition. In the process of evolution, they go through the process of positive genetic mutation but sometimes the mutation may also produce negative effect on the DNA of an species through wrong or inefficient pairing/coding. Here in this case it can be stated that the chemical sprayed on insects might have attacked the gene pool of the insects thereby producing adverse genetic mutation.
