Answer:
- illustrate the idea of demanding what one is due.
Step-by-step explanation:
Metaphors are primarily employed to compare a complex and unfamiliar object or idea with a familiar object in order to elaborate it and make it simple, easy to understand, and relatable for the readers.
In the given excerpt, King employs the metaphors like 'check,' as well as, 'promissory note' to demonstrate the idea of justice that is due to so many people. He uses these metaphors in order to give a simpler form to the serious problem of discrimination and segregation faced by a number of Americans that is solved through the 'promissory note' mentioned in the Constitution that promises due justice to the ones who suffered it. He wants every individual to get equal rights of life, freedom, and joy.