Every country is in Tier D because I get the same earnings of $2-$3 per 1000 downloads on 500MB-1GB files. I explained this once before because making only $2-$3 on 1000 downloads says that every single person downloading my files is from a country in the Other category in Tier D. That means nobody from the United States, Europe or other countries are downloading any of my files which is simply impossible.
This is not what their chart says though but behind the scenes I know for a fact all countries are in Tier D.