The correct response to highlight one significant difference between the two passages is:
King believes some tension is necessary, while Lincoln calls for unity.
This statement accurately captures the differing perspectives of Martin Luther King Jr. and Abraham Lincoln regarding the role of tension and conflict in the pursuit of social justice and national unity. Lincoln's address emphasizes the need to honor the sacrifices made during the Civil War and to move towards unity, while King's letter discusses the necessity of creating tension to highlight injustices and stimulate societal change.