All of the following are characteristics of a gang except
a. living in a low-income area
b. having questionable principles
c. committing violent/illegal activities
d. specifying rules with harsh consequences

The thing which isn't a characteristic of a gang would be specifying rules with harsh consequences - d.

Gangs usually don't really have a strict codex of law that they abide by but rather function on very fluid rules which don't necessarily include standardized ides on how people are suppose to behave.