Mike belongs to a college fraternity and tends to see his fellow students as either "like us" and part of the fraternity and sorority system or "not like us" and thus not a part of the system.  Mike therefore sees himself as being part of the 

A) out-group
B) instrumental group
C) reference group
D) in-group

Fraternity and Sorority

Social organizations, primarily found in North American colleges and universities, that are based on a system of brotherhood or sisterhood.

Out-group

A social group toward which an individual feels opposition, rivalry, or hostility.

In-group

A social group to which an individual feels a sense of belonging and identity.