Shouthern was a who remained loyal to the union were called

carpetbaggers

scalawags

republicans

Scalawags, Carpetbaggers were used to describe people from the Union who   came to "exploit" the ex-Confederacy. Republicans were the ruling political party in the Union (North). Therefore Scalawag is the answer from elimination, but it is right anyways as that was the term used to call Southerners who remained loyal to the Union.

i believe it d) heterogeneous

north atlantic treaty organization.