The Aryans created a social class system based on a person's O
A. birth
B. jobs
C. education
D. gender (male/female)

C. I know and don’t wanna bet on it

An informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.