The author's tone is ______.

A．an African and Far Eastern specialist for the War Department
B．a Noble Peace Prize recipient
C．a director of the United Nations trusteeship division
D．a board member of the NAACP

A．Mary Terrell and Ralph Bunche were two important Americans
B．Mary Terrell and Ralph Bunche were influential only in international affairs
C．Mary Terrell and Ralph Bunche helped found the NAACP
D．Mary' Terrell and Ralph Bunche both served in the U.S. government