Answer:
It emphasizes that King's critics who promote patience have not produced change
Step-by-step explanation:
The sentence "For years now I have heard the word ‘Wait!'" contributes to the text as a whole by showing that Martin Luther King' s critics who have been preaching patience have not produced change.
This shows that MLK has been told continuously to wait and after many years, nothing has been done to produce change which prompts him to continue the struggle for freedom