The correct answer is B. The change taking place in society.
This song, released in 1971, was addressing the social changes taking place in the United States. This included references to domestic and foreign problems. One of the most popular problems at this time was American citizens dissatisfaction with the Vietnam War. On college campuses around the country, students were protesting the Vietnam War and America's involvement in it. This is what Marvin Gaye is directly referencing in this song.
