In 2016, 93% of Members in the Oscars Academy Were

In 2016, 93% of members in the Oscars Academy were white. Why has it been so difficult to increase diversity in the membership of this group?

A) New members must be sponsored, and most people only have friends that look like them.
B) It has only been recently that more minorities have become directors and been cast in leading roles.
C) Minority screenwriters, actors, and directors have long boycotted the Oscars, so few want to be involved.
D) Few minorities are earn enough money to be in the upper class, which is a requirement of Academy membership.