In a Town in England, the Wings of a Local

In a town in England, the wings of a local butterfly species had a black and white pattern. Over the years, as air pollution worsened in the town, a coat of black soot often covered everything. From an evolutionary perspective, which of the following is a logical sequencing?

A) Butterflies became blacker because the ones with relatively more black on their wings were most likely to blend in with the sooty background.
B) Butterflies became lighter because the ones with relatively more white on their wings were least likely to blend in with the sooty background.
C) Butterflies became more aggressive because their behaviours were altered by the toxins that were in the black soot.
D) Butterflies morphed into moths because environmental conditions triggered an unfolding of a hidden gene.