Critical Reasoning

The mastodon, a large mammal resembling today's elephant, became extinct at the end of the Ice Age. Scientists once attributed the mastodon's extinction to the disappearance of evergreen forests at the end of the Ice Age. More recently, however, scientists have rejected that theory, hypothesizing instead that the mastodon's extinction was caused by the draining of glacial wetlands.

Which of the following, if recently discovered, would help to account for the change in the accepted explanation of the mastodon's extinction?

(A) When the Ice Age ended, many forests died off, endangering the food supply for herbivores that fed primarily on evergreens.
(B) As glaciers receded at the end of the Ice Age, glacial wetlands drained, leaving a new topography of hills and plains.
(C) Bacteria found in mastodon remains are similar to bacteria found in the remains of species that are known to have fed on evergreens.
(D) The mastodon's diet consisted primarily of water plants such as marsh grasses and water lilies.
(E) Evergreen forests were inhabited by many species of large mammals until the end of the Ice Age.