In Congress, Gangs Are Defined as Which of the Following

In Congress, gangs are defined as which of the following?

A) Official groups of members and nonmembers who meet to investigate particular problems and are sometimes empowered to write legislation
B) Informal groups formed by members as a bottom-up approach to solving policy problems
C) Group composed of negotiators from the House and Senate tasked with reconciling differences in the same bill passed by both chambers
D) None of the above