【单选题】

Which of the following, if true, would provide the best proof of the food-courtship theory developed by Austin
A．(A) The crested guan has a red throat pouch, giving the impression to its mate that the throat contains a red fruit found in its niche.

B．(B) The blue bowerbird spreads food of the same color around his nest, teaching its female young to identify the food as nutritious.
C．(C) Insect-eating birds are less successful from an evolutionary perspective than birds which bear resemblance and subsist upon bright fruit.
D．(D) The purple finch relies upon a variety of food sources, but the most nutritious food for birds general happens to be the same color as the finch's coat.
E．(E) A species of endangered sparrows resembles a food source no longer available in its niche, but the species continues to survive.