Loess Deposits in the Central United States and Columbia Plateau_____

Loess deposits in the central United States and Columbia Plateau_____ .

A) accumulated from flooding of the Mississippi River
B) originated as silt sized particles in Pleistocene glacial outwash streams and freshly exposed till
C) blew in from the dry areas in the Great Plains and southwestern desert areas
D) were originally deposited as barchanoid dunes and later redeposited by glaciers