In the early part of the 19th century the common form of Biston betularia, called typica, had a peppered appearance. Its wings were flecked with black and white, and it was well camouflaged in its favourite resting place , the pale and lichen covered barks of trees in rural England. A dark or melanistic form of the moth, called, carbonaria, was first recorded in about 1848, and presumably had existed in very small numbers before them, but by the middle of 20th century, the melanistic form of the moth had come to represent over 95% of the Biston betularia population, especially in such industrial centres as Manchester and Liverpool. This is among the most rapid of all recorded evolutionary changes. Why was there such a dramatic change in fortune of the peppered typica and the melanistic carbonaria? With rapid industrialisation, soot came to cover the barks of trees, making them black instead of pale, and also killed the lichens. Now the melanistic form was better camouflaged on the darkened bark, while the peppered form became increasingly less camouflaged and hence more easily detected and eaten by birds. The birds, which had kept the melanistic form at a very low frequency before industrialisation, now concentrated their attention on the peppered-form. Natural selection, in the form of bird predation, favoured the peppered form earlier and the melanistic form later. 
- Excert from survival strategies by Raghavendra gadagkar.

Select the option that correctly summarises the given observation in the passage.