Answer:
I'm pretty sure the answer is Greek.
The Gupta empire was made up of
Brahims a.k.a the priests
Vaishyas a.k.a merchants and tradesman
Shudras a.k.a Peasants
Kshatriyas a.k.a warrior and rulers
The fourth choice satisfies this list.
First and Last one
They did believe their culture was superior, that's obvious. During this they also got lots of benefits from the colonies.
The Nile flows from south to north because the land in southern Egypt is at a higher elevation than the land in northern Egypt.