Digital SAT Reading and Writing Practice Question #405

Historian Alana Vance has recently challenged the long-held academic consensus regarding the collapse of the ancient Harappan civilization. For decades, scholars believed that violent incursions by foreign nomadic tribes were the primary catalyst for the civilization's rapid urban abandonment. Vance, however, argues that the collapse was actually driven by severe, geographically widespread monsoonal shifts. According to Vance, a prolonged period of drastically reduced rainfall decimated the agrarian foundation of the Harappan economy, making large-scale urban centers completely unsustainable. Which finding, if true, would most directly support Vance's argument?