The answer is D. I hope this helped :)
An ambassador is the President's highest-ranking representative to a specific nation or international organization abroad. ... A key role of an ambassador is to coordinate the activities not only of the Foreign Service Officers and staff serving under him, but also representatives of other U.S. agencies in the country.
The answer to your question is King John.
“The following statement about the disenfranchisement of African Americans in the South which is true is that white voting officials administered difficult literacy tests to African American voters. Since African Americans were denied the same standard of education as American Whites, when offered literacy tests they often had trouble completing them. The voting officials were aware of this, but did it anyways, as it was another way for them to hinder African Americans from voting and from entering the larger society.”