I would say D the Billingsella Corrugata, it IS in the oldest recorded time line, so by theory, it's the oldest (Don't quote me on that, I'm not %100)
Population would go down drastically and there would be no next generation x
Rio Grande River sources: Rio Grande Natural Forest, San Juan Mountains, Canby Mountain
People migrate to the new lands, populate, build cities, created businesses, trade, settle.
