"it is obvious today that America has defaulted on this promissory note [as far] as her citizens of color are concerned." Martin Luther King Jr. who is "her"?

America

Explanation:

In his I Have a Dream Speech (1963), Martin Luther King, Jr. expressed his worries about the future of African Americans and called society to promote civil rights for every American beyond their race. To do so, King used the figure of speech known as personification, which refers to an object or animal that has been presented with human qualities. In this example, America, meaning the country or the American society, has been presented as capable of not honoring a promise.