The was created out of sandy river deposits.
a.
pamirs
b.
kyzylkum
c.
karakum
d.
amu darya

It is either A or B because they are both made out of sand but the Karakum is made from Black sand

  In modern times, with the shrinking of the Aral Sea, the extended "Aral Karakum" has appeared on the former seabed and sands of the Aral Karakum, these are made up of a salt-marshes that consisted  of finely made up minerals and remnants of alkaline mineral deposits,that were washed into the basin from former irrgated fields. The dust blown on a full east-west airstream carry pesticide residues that were found in  Aral dust, it also has been found in the glaciers of Greenland, the forests of Norway and in some of the  fields of Russia. Hope this was helpful, and have a good day!

The exchange of foods between the new and old worlds