Answer:
The correct answer is "loess".
Step-by-step explanation:
Loess is a sediment comprised of mostly silt formed by the accumulation of dust transported by glacial braided rivers. The most common loess is periglacial loess, created by floodplains of rivers transporting melt water and sediments from receding glaciers. Loess are very fertile soils that, under proper climatic conditions, are one of the most agriculturally productive terrains in the world.