The correct option is A Origin of species by natural selection
On his visit to the Galapagos Islands, Charles Darwin discovered several species of finches that varied from island to island, which helped him to develop his theory of natural selection. The Galapagos Islands are an archipelago of 13 major islands. They are home to an amazing array of unique animal species: giant tortoises, iguanas, fur seals, sea lions, sharks, rays and 26 species of native birds- 14 of which make up the group known as Darwin’s finches. These finches are considered to be the world’s fastest-evolving vertebrates because their appearance and behavior quickly adapted to this closed and rapidly changing environment.