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. It is believed that all of these species had one common ancestor and, over
time, evolved into different species. After the burst of speciation in the Galapagos, a total of 14 species would exist: three species
of ground-dwelling seed-eaters; three others living on cactustes and eating seeds; one living in trees and eating seeds; and 7
species of tree-dwelling insect-eaters. The finches varied mainly in the size and shape of their beaks. What characteristic of the
different islands most likely "selected" the most fit on each island?

A)climate

B)predators

C)competition

D)food sources