Which of the following, if true, best casts doubt on the argument? A. In addition to elderberry, the Canadian elk also consumes loganberries, which are expected to also begin growing at more northerly latitudes. B. During the summer months, many Canadian elk are hunted both for sport and for their meat. C. The grizzly bear, the Canadian elk's primary predator, has also started moving north into the tundra. D. The permafrost, the region above the tundra, in which the temperatures never reach above freezing, will unlikely see elderberry growth. E. Increasing temperatures have created conditions too warm for elderberry growth in the southern half of the Canadian elk's traditional territory.