What Did Darwin Conclude from the Observation That There Are

What did Darwin conclude from the observation that there are no rabbits in South America?

A) Rabbits cannot live in South America because it is too warm.
B) Rabbits cannot live in South America because they do not have a good food source.
C) Rabbits evolved somewhere else and had no means of reaching South America.
D) Rabbits were originally found in South America but went extinct.
E) Rabbits in South America evolved into guinea pigs and thus are no longer present.