The evolution of the peppered moth is an example of colour variation in the moth population as a consequence of the Industrial Revolution. There was an increase in the number of dark-coloured moths due to industrial pollution, and a reciprocal decrease in the population in a clean environment. Hence, the phenomenon is called industrial melanism. It is the first recorded and experimented case of Charles Darwin's natural selection in action, and a classic example of evolution. Sewall Wright described it as "the clearest case in which a conspicuous evolutionary process has actually been observed". The dark-coloured or melanic moths (carbonaria variety) were not known prior to 1811. After field collection in 1848 from Manchester, an industrial city in England, the frequency of the variety was found to have increased drastically. By the end of the 19th century it almost completely outnumbered the original light-coloured type (typica variety). The evolutionary importance of the moth was only speculated upon during Darwin's lifetime. It was only 14 years after Darwin’s death, in 1896, that J.W. Tutt presented it as a case of natural selection. Conservation, skin diseases and acid rain are not examples of natural selection. Thus, option C is correct and other options are wrong.