Ash Layers from the Three Most Recent Caldera-Forming Eruptions at Yellowstone

Multiple Choice

Ash layers from the three most recent caldera-forming eruptions at Yellowstone (2.1, 1.3, and 0.64 million years ago) stretch

A) from Wyoming to Colorado.
B) from California to Washington,
C) from one side of Yellowstone National Park to the other.
D) from Canada to Mexico.