单项选择题
A．establish that enough food could have been grown to support the Anasazi's survival
B．argue that the Anasazi's past behavior would indicate their likely future behavior in the case of a Great Drought
C．suggest that the repetition of droughts was taking a cumulative toll on the fertility of the Plateau
D．argue that the evidence which points to the existence of a Great Drought may actually be related to earlier droughts
E．affirm the notion that the Great Drought may have been exponentially more severe than prior droughts