Answer: C. The people who have worked hard to make the civil rights movement happen but will never be given an award
Explanation: In Martin Luther King Jr., Nobel Peace Prize acceptance speech, 1964, in this metaphor he is comparing the people who have worked hard to make the civil rights movement happen but will never be given an award, to a flight's ground crew. He is comparing the unknown people who make flights possible through hard work and will never receive an award to the people who made the civil rights movement possible.