Question ID:PT62 S4 Q7 Passage:Researcher:  Over the course of three decades, we kept records of the average beak size of two populations of the same species of bird, one wild population, the other captive. During this period, the average beak size of the captive birds did not change, while the average beak size of the wild birds decreased significantly. Stem:Which one of the following, if true, most helps to explain the researcher's findings? Correct Answer Choice:CChoice A:The small-beaked wild birds were easier to capture and measure than the large-beaked wild birds. Choice B:The large-beaked wild birds were easier to capture and measure than the small-beaked wild birds. Choice C:Changes in the wild birds' food supply during the study period favored the survival of small-beaked birds over large-beaked birds. Choice D:The average body size of the captive birds remained the same over the study period. Choice E:The researcher measured the beaks of some of the wild birds on more than one occasion.