The correct answer should be D.) Declines in poisonous, non-edible mushroom species in cool climates. Although question B does provide evidence that Global warming could be the cause of the declines, it still doesn't disprove the theory that overharvesting could be the cause as well. Question C could be caused by a number of things, such as deforestation, a local change in climate, removal of agricultural pests, ect. Question A supports the hypothesis that overharvesting is the cause of the decline, instead of disproving it. Hope this helped!
They both hunt for food and will ruthlessly kill you before you can cry, "MAMA!"