Part A
The claim that Reverend Martin Luther King Jr. makes in his "I Have A Dream" speech is:
There are allies outside of the African American community who understand that until all people are free, no people are free.
Part B
The evidence from King's speech that is most relevant in supporting the claim identified in Part A is:
"...for many of our white brothers, as evidenced by their presence here today, have come to realize that their destiny is tied up with our destiny."