This Wind-Blown Dust Deposit (Loess)from Tibet

This wind-blown dust deposit (loess) from Tibet

A) was deposited by a huge flood of seawater that covered the land at the time of the dinosaurs.
B) began as clay and silt that were produced by grinding of rocks along ice-age glaciers.
C) forms a worldwide layer associated with a well-known extinction of dinosaurs.
D) All of these are correct.