The answer is A) That the seed eating species would disappear, because the seeds would disappear followed by the finches that ate those seeds and the other finches that eat other food like insects would thrive.
The energy-rich compound needed by organism is : Carbohydrates
Carbohydrates consist of the combination of the existing Carbon, Hydrogen, and Oxygen alone.
For human, The source of carbohydrates could be found in almost every food, but the huge amount could be found in rice, potato, corn, cassava, oatmeal, etc
hope this helps