The correct answer is A, Lincoln: birth of freedom, King: righteousness' sake.
Lincoln said "birth of freedom" to help the nation come to terms with the end of slavery and define the meaning of freedom.
Righteousness is defined as the quality of being morally right or justified.
Both of these phrases best support the theme of equality for all, because they show that freedom is for all and that the morally right thing is that everyone is treated equal.
Righteousness' sake = For the sake of righteousness, the rights of equality must be distributed equally to everyone.
Answer is A.
Hope this helps. - M