In England, before industrialization in 1860, it was observed that there were more white-winged moths on tree trunks than dark-winged or melanised moths. But after industrialization in 1920, there were more dark-winged moths in the same area. Before industrialization, the tree trunks were covered by white-coloured lichens. In that background, the white-winged moths survived but the dark-winged moths were eaten by predators. During post industrialization period, the tree trunks became dark due to industrial smoke and soot. Therefore, the white winged moths could not survive due to predators but dark-winged moths survived, i.e., the moths that were hidden in background survived. Thus, industrial melanism supports evolution by natural selection. So, the correct answer is 'Natural selection'.