The correct answer is A. protective resemblance with the surrounding.
Industrial melanism is a type of natural selection in which the frequency of a dark-colored morph of an organism increases in populations living in industrial areas. This is because the dark-colored morphs are better camouflaged against the soot-covered trees and other surfaces in these areas, and are therefore less likely to be eaten by predators.
Option B is incorrect because drug resistance is the ability of a microorganism to withstand the effects of a drug that once could successfully treat the microbe.
Option C is incorrect because defensive adaptation of skin against UV radiations is the process by which the skin produces melanin, a pigment that protects the skin from the sun’s harmful UV rays.
Option D is incorrect because darkening of skin due to industries is not a biological process, but rather a cosmetic effect caused by exposure to pollutants.