In American Hospital Association V

In American Hospital Association v.NLRB, the U..Supreme Court upheld the NLRB's health care industry bargaining unit rules and the power of the NLRB in order to establish:

A) ​prima facie case through disparate impact treatment.
B) bargaining units through its rule-making authority.
C) trade union through its discretionary power.
D) hiring hall through its mandatory power.