C. During His speech "Our God is Marching On!"Was Martin Luther King aware that he was speaking to people in that moment as well as to people in the future? Who are those people?

Yes, at the time of his speech, he left what was being said and how it would impact other people, black and non-black people. His objective was precisely that, to make people hear all the bad things that black Americans had to live daily. Throughout his speeches he opened the eyes of many people and showed them the horrible way African Americans were being treated.