The Fate of the Donner Party Demonstrated

The fate of the Donner party demonstrated

A) how important it was to cooperate with the Indians.
B) how difficult it was for groups of families to successfully cross the Great Plains.
C) the unreliability of published guide books about the Great Plains and Rocky Mountains.
D) the high moral principles and ethical values of emigrants on the Overland Trail.
E) the limited ability of poor families to reach the far west.