Which of These Statements About Managing Diversity Is True

Which of these statements about managing diversity is true?

A) Managers can improve the level of diversity in a workplace, but because the workforce is becoming ever more diverse over time, managers can't really derail diversity.
B) Managers are at a higher level than the employees they supervise, so it isn't realistic to expect managers to be role models when it comes to encouraging diversity.
C) Even when a manager is aware of some diversity-related issues, unconscious bias can creep into that manager's beliefs and behaviors.
D) Diversity issues have become easier to manage in most workplaces now that the issue of diversity has gained more attention.