Billy Joel uses to "establish unity between the lines", I assume you're talking about "We Didn't Start the Fire"? I assume this because it's one of the most infamously deconstructed songs in both History and English classes.
Billy Joel uses two major literary tactics in this song that establish unity and make it so catchy and memorable. First of all, Joel plays off the beat of the song by singing the lyrics in a linear fashion (like a shopping list). Notice the music itself doesn't change between the chorus and the rest of the song.
Secondly, and more importantly, he take advantage of the allusion in his lyrics. Billy Joel's "We Didn't Start the Fire" is full of references to real events and icons of history. An allusion is literally just a reference to something that you could just understand.
The correct answer is C. Noun
Explanation
A noun is a type of word that is used to designate beings, entities, or objects. One of the characteristics of nouns is that they have a masculine or feminine gender and a singular or plural number. According to the above, in the text of the question, the word Courage of the sentence "Ahn thought she would not have the courage to initiate a friendship, but she underestimated herself." is used as a noun because it designates courage as a singular entity. So the correct answer is C. Noun.
There is class inequality, like how rich people can bail themselves out of jail or are given easier bonds, for doing the same crime a poor person does.