The Ice-Free Corridor Was

The ice-free corridor was:

A) a thin strip of land along the west coast of North America that allowed people to journey south at the end of the Pleistocene
B) a corridor of land between the Cordilleran and Laurentide ice sheets through which people may have journeyed south at the end of the Pleistocene
C) a corridor of land between the Rocky Mountains and the Great Plains that was free of glacial ice as a result of the "ice shadow" present on the eastern flank of the mountains through which people may have journeyed south at the end of the Pleistocene
D) a strip of ice-free territory in western Pennsylvania that allowed the inhabitants of Meadowcroft Rockshelter to migrate there a few thousand years before the Paleoindians