XYZ Association,a Carpenters' Trade Union,adopts Guidelines Intended to Curtail Questionable

XYZ Association,a carpenters' trade union,adopts guidelines intended to curtail questionable and pervasive activity by its members.Which of the following statements is true about the relationship between XYZ and its members?

A) XYZ Association may exert pressure on members to stop engaging in questionable business practices that may harm all firms in the industry,but their pressure is ineffectual.
B) Because trade associations exist for the benefit of their members,any measure XYZ takes will benefit the members and the association.
C) XYZ may make rules to govern its members,but it has no means to enforce them.
D) XYZ may make codes of ethics and rules to govern their members but it must also make sure that these codes and rules do not breach antitrust laws.