Darwin recorded distinct species of finches on different islands in the Galapagos. The images below show two species of finches he observed. On island X, he saw both species of finches. On island Y, he only saw the finch on the right. Based on these observations, what is the most likely conclusion Darwin would have made?

A.
The finches on island X developed different beaks as they grew, but the finches on island Y kept the same type of beak.
B.
There were frequent environmental changes on island Y, but a relatively stable environment on island X.
C.
The finches on island Y chose to have larger beaks, but the finches on island X chose to have a variety.
D.
There was a variety of food available on island X, but there were only large seeds and nuts on island Y.